Santel M180 F10 Rumak Maksutov first light

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Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Sat Mar 07, 2020 12:14 am

Hi,

I had the first good day when I have been at home for the year so far.

Had the Vixen VMC110 F9.4 out with a PST stage 2 mod and one of my 0.15nm Omega H-alpha pair in a Celestron/Skywatcher Moon filter just losely held in as the Comb Blocker. Which looks like a production filter not a cosmetic seconds normally supplied with the 2 Filter 'Old as New' sets. After a lot of effort in baffling and surface treatments I had a nice view of the whole sun against a dark background. I could see two prominences but a bit fuzzy. And a hint of chromosphere details.

Having use the Vixen for 2 years without issues I decided it was time to try the Santel.

I added a M42 to 2" nosepiece with a M48 to T2 ring in the front to give me a 2" barrel to go in the Santel 2" focusser, in the middle of the Vixen adapter. No problems reaching focus.

This gave me a nice larger and better resolution view of the two prominences similar to shown in Solar Chat today.

Waved my Laser remote thermometer about. The alloy front cover on the seperate secondary mirror was about 15Deg C above ambient. Nothing anywhere in the telescope appeared much above ambient. Pointing the laser up the eyepiece showed a typical 24Deg C.

I did try my new Daystar Chromosphere in as well with 2" Baader 35nm as a ERF and 1.25" UV-IR on the front of the Quark. Too dim at F42. When I took it out the holder for the Baader was not at all warm.

Need to do some baffling work on the Santel. Rodastro is talking about making a push up baffle from the back to preserve it as a nighttime scope. I have 180 grit painted with Black2 up the baffle at the moment.

I look forward to using this mod with the option of two 0.15nm Omega filters as a DS when Rodastro kindly does a mod to a 2" diagonal to hold and tilt the filters, as he uses on his Zeiss. I call the Santel 180 a 'portable 6" F15 Zeiss' as not far off the performance. Sits nicely on a Vixen GP2.

I used the Daystar Quark Chromosphere in a Opticstar 80mm F5 refractor and could see details on the Suns surface and just faintly the two prominences. Try a couple of larger refractors next.

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by marktownley » Sat Mar 07, 2020 9:03 am

Sounds good. Got some pictures you can share?


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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Sun Mar 08, 2020 11:05 pm

Hi

Radiation and heat status in the telescope.

Version 2. Closed Tube unlike the Visac. Details about the 35nm from Merlin:

I am ignoring the secondary obstruction. Its black and the front absorbs some heat though is clearly radiating more away at 24C over ambient. Half the secondary heat load?

Primary 18cm diameter

Notional area 0.0 x 0.09 x Pi M**2 = 0.025

1000 W/M**2 x 0.025 = 25w in.

I have used 8% for absorbtion of a single coated aluminium mirror or a glass lens or filter.
More checking the mirrors are SiO overcoated Aluminium 89% reflectance. So 11% absorbtion?

25 X 0.11 = 3W absorbed

22w reflected to secondary.

22 x 0.11 = 2W absorbed

20W reflected to Baader 35nm ERF. 35nm transmitted which is 14% from Merlins Post.

20 x 0.14 = 3W Passed through 35nm

So 17w reflected back to secondary.

3W of red light passed to the PST Etalon

I have a Omega 40nm blocker in place of the PST Collimating lens so will pass the 3W on.

The PST etalon passes 1/6 of the energy in the combs from an Italian article.

3W x 1/6 = 0.5W passed out in the combs

Will have 35 combs 1nm apart.

0.5W x 1/35 = 0.014W out as a single Comb

0.014w passed to the eyepiece.

Suns image 18mm.

Suns image area 0.009 x 0.009 = 0.000081 M**s

Watts / M**2 = 0.014 / 0.000081 = 176W / M**2 One 5th full sun light.

Calculate temperature need to radiate away the heat on surfaces by using building heat loss fromulae reversed.

Open air conductance 17W / M**2 x K Vixen. Front of Santel Secondary holder, cosmetic cover removed.

Still air conductance 9W / M**2 x K Inside Santel

K = 1

Primary 0.025 M**2

9W x 0.025 = 0.225

K = ( 2W Primary + <=2W from ERF via secondary ) / 0.225 = 17.8K over ambient

Secondary 6cm diameter.

M**2 = 0.03 x 0.03 x 3.142 = 0.0028

Radiation from black back of secondary holder
17W x 0.0028 = 0.048

K = (2W Primary + <=2W from ERF) = 4W /0.048 = 83K over ambient.
The silvered mirror of the secondary will be radiating away as well.

25W into telescope. Roughly 2x2W absorbed in primary and 2x<=2w absorbed in secondary so 8W to radiate out of inside of sealed tube.
14W reflected back out, 3W into Etalon.

Area tube = 0.180 x 3.142 x 0.480 + 0.090 x 0.090 x 3.142 = 0.272 + 0.03 = 0.3 M**2

17W x 0.3 = 5.1

K = 11W /5.1 = 2.15K above ambient

On both Maksutovs pointing the Laser guided thermometer up the eyepiece gave 24C.
As they are both F10 and the intensity on the optics the same then I suppose they should be the same.
Is it not seeing the hot secondary temperature, because its silvered and not a black body and so reading lower?

Need to make up a test panel for the laser thermometer, different finishes on surface with back to the Sun so same temperature.

Andrew.
Last edited by AndiesHandyHandies on Wed Mar 18, 2020 9:14 pm, edited 1 time in total.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by Merlin66 » Mon Mar 09, 2020 5:25 am

I think the equation you use is interesting....
Including all the solar energy up to 2500 A in NIR, the 35nm Baader will transmit approx 27%
The etalon based on 1A comb every 10A spacing = 1/10
When considering the pre-blocking filter you need to look at the energy distribution (W/m^2/A) which varies with wavelength.


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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Mon Mar 09, 2020 9:03 am

Hi Merlin,

The equation I use is for free air so I could be a bit hotter?

Where did you get the 27% from please?

There was an article which stated 1/6 as I recall, will the skirts on a simple etalon give some extra trasmission. Its not critical for my post.

Thanks. Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Mon Mar 09, 2020 9:04 am

Hi

Bobs ERF is supposed to block long IR.

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by Merlin66 » Mon Mar 09, 2020 9:53 am

Andrew,
I'll upload the detailed calc...but based on a full UV-NIR solar radiation is comes in approx 27%.
I haven't seen any spectro transmission curves (UV- NIR) for "Bobs ERF" so can't comment.


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Re: Santel M180 F10 Rumak Maksutov first light

Post by Merlin66 » Tue Mar 10, 2020 3:25 am

First: Baader like most astronomical filter suppliers provides transmission data up to 1500nm. Additional data came from Hobel.

The solar irradiation (sea level) has 5% in UV, 43% in Visual and 52% in NIR. Total solar energy is 1000 W/m^2.
The solar energy intensity (W/m^2/nm) varies across the spectrum. At Ha , around 650nm the intensity is 1.3. In the NIR it "averages" 0.2.
The atmospheric absorption band in the NIR affects 200nm. Hence NIR, beyond 1500nm = (2500-1500-200) = 800nm

The bandwidth of the Baader D-ERF is FWHM 80nm, 98% at Ha. The Hobel chart shows the transmission increases beyond 1500nm and averages 60%.
The bandwidth of the 35nm Ha Baader CCD filter is 35nm at Ha, at 95%. It is assumed to have a similar curve to the D-ERF in the NIR.

Some numbers:
D-ERF
Transmission at Ha =80 x 1.3 x 0.98 = 102 W/m^2
Transmission in NIR = (800) x 0.2 x 0.6 = 96 W/m^2
Total transmission: 198 W/m^2 (20% of the total solar energy)

35nm Ha Baader
Transmission at Ha = 35 x 1.3 x 0.95 = 43.2 W/m^2
Transmission in NIR = (800) x 0.2 x 0.6 = 96 W/m^2
Total Transmission: 139.2 W/m^2 (14% of the total solar energy)
Solar_Spectrum.png
Solar_Spectrum.png (36.25 KiB) Viewed 12843 times
Solar Energy Distribution.png
Solar Energy Distribution.png (69.77 KiB) Viewed 12843 times
Baader-D-ERF.jpg
Baader-D-ERF.jpg (98.1 KiB) Viewed 12843 times
baader-h-alpha-35nm-ccd-filter-1-1-4--300.jpg
baader-h-alpha-35nm-ccd-filter-1-1-4--300.jpg (112.75 KiB) Viewed 12843 times
(Comment: My earlier estimate was based on a higher transmission in the NIR and no account of the heavy atmospheric absorption band in the NIR)


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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Tue Mar 10, 2020 9:08 am

Hi Merlin,

Thanks for that.

I was having a look around for absorption in mirror coatings. But they only specify reflectance. I assume some light is scatttered.

Santel was a former Intes-Micro enployee who used their mirror sets, at least to start with it appears.

Intes used LK7 for the mirror and LK5 (Pyrex) for the secondary so I should not melt it.

The mirror is aluminium with SiO2 coating and reflects 89%. Some must be scattered.

Its a trade off using a cheap internal Baader ERF against a full aperture DERF and for a few days a year and not economic for me.

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Tue Mar 10, 2020 4:46 pm

Hi Merlin,

Pictures deleted.

The two h-alpha filters were dated as purchased. The background one is for information so date not relevant.
Showing Bobs 40nm blocker stops IR out to the limit of the scan. It does have a bit of blue leakage.

Andrew
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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Fri Mar 13, 2020 10:02 am

Hi

The cheap sets Bob sells are cosmetic defects for the H-alphas.

The first set we had had one h-alpha bonded to the 40nm blocker but had large no of reflections so were returned.

I am afraid I caused AstroRod time and money as we only found out later solid filters should be used near focus
and building large collimators for his set up was a waste of time.

Bob forgot we sent two sets back and the second he sent do not look like cosmetic rejects.

Andrew



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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Sat Mar 28, 2020 10:58 pm

My pants are not on fire!

Some temperature measurements on this and other telescopes:

Santel M180

After developing a Stage2 PST Mod on the Vixen VMC110 I decided it was safe to try it in this telescope.

I bought a cheap yellow laser pointed remote thermometer.
It is defaulted to 0.95 emissivity surface, organics, matt black, glass all are that. Looking down the front or removed elements front.
Pointing it up the telescope I refer to the measurement as BBE - Black Body Equivalent, just a guide to energy it sees.
The detection area is a cone and some waving about is needed to get a maximum.

I first used a 2" Baader 35nm on its own up the 2" Focusser. The front of the PST Mod actually goes part way up the baffle tube.
So its not behind the Collimator lens in a closed tube and has an open back

Measuring ........................................... Up the scope BBE C .............. Down on the removed element Temp C

2" Baader 35nm .................................... 66 / 74 /87 ......................... 30 / 40


M180 .............................................................. Vixen VMC110 ......... M180 ............................. Vixen VMC110

EyePiece ............................................ 23 ......... 20.5 .................... Beloptic in eyepiece 25 ...... 21.3
No-Beloptic KG3 in Eyepiece .................... 28.1 ....... 22
Omega 1.5A 25mm as Comb Blocker ........... 40 ......... 27 ................................................... 24 ...... 19

[ Diagonal ......................................... 53 ......... 30.5
[ Set with
[Re-focus lens in front ................................................................................................ 23 ...... 16.7

PST Omega 40nm ERF in Collimator Holder .. 80 ......... 32 ................................................... 26 .......15.5

[ Baader 1.25" 35nm ERF ....................... 199 ........ 122
[ Set with
[ Collimator Lens ..................................................................................................... 57 ......... 17.4
[ Side of holder ...................................................................................................... 51 ......... 16.5

The M180 has a corrector plate so closed tube. The VMC110 has a spider so open tube and a second port over the Baader holder.

The thermometer could not be used without the 35nm so I looked at illuminted spot on the black dustcover
Red from Baader 23 - From Merlins figures would have thought this less?
White ........... 47

My assumption about the secondary heating seems too high. Figures for SiO overcoated mirros reflectance are 89 or 91.
I took the cosmetic cover off the secondary holder. So bare black mirror holder.
The steel pier is painted black. I got the same or similar temperatures off the pier and back of the secondary holder.
So it seems the secondary cannot be as hot as I calculated. Is most energy scattered by the mirror?
From the net the secondary is Pyrex so I am not going to melt it anyway.
Also the inside and outside of the primary mirror baffle are at ambient.

I now have a Daystar Quark Prominence and most people use these with just a UV/IR, which came with mine, in a refractor.
I have added a red Dichoric after the UV/IR. And use a 2" Baader 35nm spaced up the tube.
90mm F6.7 TS Triplet

BBE Front Element Temp
Eyepiece and Belpotic KG3 .... 24 / ( 24.3 Reduced ) ............. 34 Beloptic Different Emissivity?
..................................... 24 Seems a Maximum I have seen in all scopes measured with Beloptic KG3
Eyepiece ......................... 24.4 .................................. 25.1

Quark back Filter .............. 49 / ( 54.9 Reduced )

Quark Front
UV/IR and Dichoric Red ...... 17.8 / ( 28.3 Reduced )

Diagonal ........................ 109 To 2" 35nm Baader

Looking down through lens .. 109??


127mm F7.5 Meade 'dealer sample' Triplet

BBE Front Element Temp
Eyepiece and Belpotic KG3 ... 10.7 ................................... 20.2

Quark back Filter .............. 37.2

Quark Front
UV/IR and Dichoric ...................................................... 13.2

Diagonal ........................ 135 To 2" 35nm Baader .............. 35 / 24 Side 5.9

Looking down through lens .. 122?

Some figures may be lower due to contrail haze. Clear skies give the 24 up the eyepiece.

So I am happy with the M180 as the image is larger and more detail can be seen.

I have not done any baffling on the M180 yet like the Vixen, which gives a black reflection free background, so do have some reflections visible, and there is 3.5x more light to baffle.

Cheers. Andrew.
Last edited by AndiesHandyHandies on Mon Mar 30, 2020 12:05 pm, edited 1 time in total.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by Carbon60 » Sun Mar 29, 2020 6:38 am

Any solar images, Andrew?

Stu.


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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Sun Mar 29, 2020 8:21 am

Hi

I have not got round to imaging yet.

I had one try some time ago with a little QYH and the PST but could not find focus.

When we get some clear skys I could have a try.

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Mon Mar 30, 2020 4:06 pm

Hi

I think my attempts to calculate temperatures from a buildings formulae might have been flawed.

Going back to my Physics past I tried Boltzmans Law. I did write a program to calculate the temperate of an exploding wire with current through it as we for some reason I forget were blowing bits of wire up with a current. Using various laws including Boltzmans.

The Baader 35nm area in the M180 measures as 57C.

So

W = 5.67 x 10-8 * K * Area

0.09 x 0.09 x 3.142 = 0.002 M**2

W = 5.67x 10-8 * ( 273 + 57 ) ^ 4 * 0.002 M**2

W = 0.85

For 283 roughly ambient W = 0.09.

Assuming 6% absorbtion in the Baader thats 1.32W. So in the right ballpark.

There will be some conduction in the holder. Less in the enclosed Santel.

The Vixen was 17.4C for the Baader.

So 17.4 * (0.09 *0.09) / (0.55 * 0.55) = approx 47C

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Thu Apr 02, 2020 9:33 pm

Hi

Thinking about the thermal load on the ERF I decided to clean the Black paint of the front ring of the holder for the Collimating lens with the Baader 35nm behind it. And polish it up. When observing a prominence in the PST Mod sweetspot a lot of Sun is shining on the ring.

At 6pm here with a bit of haze I measured 34C looking down on the ERF and 31C on the black side of the holder.

I could see the triangular prominence in Stefi's image nicely with the little bit sticking out of the side. Despite poor seeing with windy conditions.

I always seem to get the best view with my 25mm Clave' Plossl. Putting on more magnification seems to loose contrast and brightness.

The primary baffle and the optical axis are a bit out of alignment now I can see the bright ring on the front of the holder is nicely prominent. Needs a bit of adjustment.

More reflections apparent than in the Vixen VMC110. Have to wait till I can see my engineer again to baffle up the Mak.
In the Vixen part is intercepted by the tight baffle on the top of the primary mirror baffle which only just lets the bright cone in when the Sun is centred.

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Sun Apr 05, 2020 9:43 am

Hi

Clear day today.

The nosepiece is warmer than last session by feel.

I can see a couple of proms at 10pm one large arc going down and one above it.

I added the second Omega Bobs 0.15nm to the front ofthe eyepiece, in plastic Moon filter bodged in at an angle, like the Comb Blocker one.

I could then see a faint arch prom at 2pm with a litle tree below it. Due to the Sun being dimmer.

Scanning across I can granulae and a little dark mark between the two proms going form 1am to 7pm.

Trying a few aff the wall mods today.

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by marktownley » Sun Apr 05, 2020 10:43 am

Good luck, clouds arrived for me now and they're heading your way. Got a picture of the scope you can post?


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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Sun Apr 05, 2020 8:05 pm

Hi,

Its a standard Santel Rumak Maksutov just like an Intes-Micro one. He was an optician who went on his own for a bit when they stopped trading. He seems to have used the same materials as Intes. After a while he transferred to making large professional scopes.

It does not use a moving mirror but a simple focusser on the back. It came with a faded orange electric Moonlight but I took it off.

180mm F10 so ideal for a PST Mod.

It was clear first thing and the field was pretty black like the Vixen. Last time there was some haze and lots of visible reflections.

The advantage of the design is that it has a flat field with no colour. In the green optics book all the dots are inside the little circles.

When the seeing is good they give the best views according to Roland of Astro-physics.

I need to set up some photo account I suppose.

I was trying my first idea but came over cloudy by the time i had set up.

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Thu Apr 09, 2020 8:50 am

Hi

There is a similar scope to mine on ABS

https://www.astrobuysell.com/uk/propvie ... iew=160182

Another outfit of old Intes or Intes-Micro opticians. Dose STF mean Santel Telescope Factory?
The tube and mounting plate look the same as my Santel.
The opticians used the same components and I assume coaters as Intes.
Because the mirrors are spheres its easier to get a good figure so the coatings are smoother.
Looking around the mirrors are LK5 a Pyrex like boro-silicate glass so will not melt.
And the reflectance is 97% so I assume mine is the same. And this explains why my secondary is cooler than I calculated.

Primary 18cm diameter

Notional area 0.0 x 0.09 x Pi M**2 = 0.025

1000 W/M**2 x 0.025 = 25w in.


More checking and assuming common coaters the mirrors are enhanced? SiO overcoated Aluminium 97% reflectance.
So a lot of light loss is scatter not absorption in the coating.
So assume 2% absorbtion, may be less.

25 X 0.02 = 0.5W absorbed

24.5w reflected to secondary.

24.5 x 0.02 0.49W absorbed

Heat calculation

Still air conductance 9W / M**2 x K Inside Santel
Moving air conductance 17W / M**2 x K outside Santel

K = 1

Primary 0.025 M**2

9W x 0.025 = 0.225

K = ( 0.5W Primary + 0.49W from ERF via secondary ) / 0.225 = 4.4K over ambient

Secondary 6cm diameter.

M**2 = 0.03 x 0.03 x 3.142 = 0.0028

Radiation from black back of secondary holder assuming contact and IR from back of secondary
17W x 0.0028 = 0.048

K = (0.49W Primary + 0.45W from ERF (Passes 10% from Merlins Calculations) = 0.94W /0.048 = 19.6K over ambient.
The silvered mirror of the secondary will be radiating away as well. So should be cooler.

Andrew



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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Tue Apr 14, 2020 6:45 pm

Hi

I could see the proms in this image this morning so that will do for me.

http://halpha.nso.edu/keep/hag/202004/2 ... 4910Th.jpg

Cheers. Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by marktownley » Tue Apr 14, 2020 7:32 pm

Glad its working well Andrew. Excellent given todays seeing.


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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Tue Apr 14, 2020 10:51 pm

Hi,

Yep it was a bit blurry at times.

I had all 4 scopes out on the deck at one stage.

The M180 showed the proms well. Nice colour and good contrast.

I got the VMC110 out and it had the better black background due to the secondary and primary baffle tube extra baffles.
After the lockdown hopefully get my friend to do similar for the M180. He wants to push temporary baffles up to preserve it for night time use.

I had the Meade 127mm Triplet out. Fortunatley moving the collimator lens forward for the VMC110 means it reaches focus in all scopes so far.
The image is a bit small. You can see the two PST reflections moving as a pair. As the focal length gets longer they drift away from the Suns image.
One overlaps at shorter focal lengths.
I am puzzled as to why I get two images which move as I tune the PST. Is that normal? Should the etalon be tilted?
The proms had that refractor feel.
There is some haze caused by dispersion from the lens.

Also I had the new Quark Prominence out. And had time to try the tuning out step by step.
I was first dissapointed at how dim it is compared to the PST.
That was at the setting the old owner I bought it off used.

I have a 90mm F6.7 Triplet so I used a reducer on it I have devised. Originally for my faster 8" GSO F4 project.
I tried camera macro lenses as achromatic doublets of lower power then the Antares ones which are not very good.
I use -330mm 3 Dioptre ones pushed down inside the focusser. Placed to give a 0.7x reduction.
A 55mm for the 90mm. The eyepiece holder ring unscrews.
So I go 55mm to 49mm to 48mm to T2, T2 extension tubes, and then T2 2" holder through the ring. Fortunately the 3 screws are long enought to grip the T2 extension tubes. I had to get my Baader T2 prism out to get enough backfocus. 2mm spare.
This has made the image a bit brighter. I have not checked the power change yet, boring pictures of a brick wall.

I started out to the right with the tuner knob, which showed details on the surface, black features, maybe one spot.
At this point I could see one prom but at one edge, I assume a tuning bandwidth/centering effect.
As I turned it left I was able to see the prom more to the centre.
At half way I started to see proms. The Sun was less dark red as I moved left.
Going further I could see all the proms. But not as contrasty as the M180 or 127mm.
So I was much happier!

The PST Mods are OK for proms which show in the sweet spot. The Mak is easy to set up on a Vixen GP type mount and put the PST Mod unit in.
The Vixen has proved it worth in the development stage and light and portable.

And hopefully I will get some images with the Quark somewhere as good as its review in Astronomy Now.

Andrew.



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Re: Santel M180 F10 Rumak Maksutov first light

Post by marktownley » Wed Apr 15, 2020 6:25 am

Good review of the days activities Andrew. Is your Quark the one that was used for the review in the S&N magazine? Did you get it off Gary or had it another owner inbetween?


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Re: Santel M180 F10 Rumak Maksutov first light

Post by AndiesHandyHandies » Wed Apr 15, 2020 8:30 pm

Hi Mark,

It apparently had another owner who said it was the one reviewed in AN. So hopefully he is right!

I am thinking of a 100mm F5 with my 0.7x reducer would be the biggest aperture I could get with the image fitting in. F3.5 and 350mm fl much like the 60DS Quark.

I had a go at a 2x barlow on the 127mm today but not enamoured. Putting a 12mm Plossl in does match the M180 for scale otherwise.

Went back to the M180, easier to manage. Could see the hedge and a spike opposite. Some haze with a few dark bits. Of course with the sweet spot all over the place not possible to put a small chip camera on centre. Unless you add a tilter? I have M48 and T2 ones. Still its the best option for visual so far. With more light makes it easier on the eye to cope with processing the seeing. Asking advice on CN for a good 18mm to try. Edggie is pushing for binoculars which will be popular with my friend.

Put the reduced 90mm on with the Quark.
Tried to take an image with the GX80 but focussing is an issue in daylight. Put a C-mount 0.5x on and the Sun then fits in the frame.
Tried my best to focus and then left it to Intelligent Auto. Just a blob. You can see spiricules maybe and some ring feature in the image, sort of sweet spotting?

I do plan to get my dismantled observatory from Brum back up this autumn. Spent a bit of time on the wooden base ring and wheels treating and painting. I am going to make it walk-in this time. Just 5 longer uprights. I have the wooden frame and brackets. Thinking of a alloy sheath, its a round pill-box, vinyl wrapped with an old star chart. My friend Paul collects old charts and books. Easier for imaging then when screens in the dark. Even then my friend has a black hood over the screen and a black towel over with his Quark.

Cheers. Andrew.



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