Newly arrived 295mm D-ERF

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RaymondTSE
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Newly arrived 295mm D-ERF

Post by RaymondTSE » Mon May 29, 2017 2:49 pm

Dear all,

A slight surprise when an EMS parcel arrived toay (slightly ahead of my expected schedule) from Ukraine.

After careful unwrapping of 2 carton boxes, I found a pearl white platic filter cell.

I give myself a pleasant smile when I find the large filter in good shape, clean and free from visual defect. No crack/damage/scratch.
Thanks to Valery for carefully wrapping up the filter.

The next step is to design an aluminium adapter to mate the heavy duty plastic filter cell (2.4kg for glass filter+filter cell) onto the top of my 12.5 inchF5 dob.

The picture shows an inner thick blue circle which is the OD of my 12.5 inch/318mmF5 reflector mirror.

The larger thick blue line is the 330mm clear aperture of my Dob's upper assembly.

Eager to see the visual differences between a Lunt 152mmF6 T/Ha through B1800 blocking filter & a large D-ERF (282mm clear aperture within the plastic cell) with Quark Combo after TV4x/5X powermate.

Raymond
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Re: Newly arrived 295mm D-ERF

Post by Montana » Mon May 29, 2017 6:02 pm

Very nice :)

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Re: Newly arrived 295mm D-ERF

Post by christian viladrich » Mon May 29, 2017 7:58 pm

Impressive and very exciting !
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Re: Newly arrived 295mm D-ERF

Post by Derek Klepp » Mon May 29, 2017 9:47 pm

Raymond I look forward to the results.

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Re: Newly arrived 295mm D-ERF

Post by Valery » Tue May 30, 2017 1:07 pm

Raymond,

Glad to know your filter arrived quickly and in a safe shape.

This plastic "box" is the cell of the filter for C11 telescope (which you intend to use in a future).
So, the filter can be used with this cell right out of the box. It has a bayonet secure system.
Upper (wider) cup can be used for temporal filter cover on the telescope.

Better to remove the filter after each observing session and store it with both dust cups.
After each observing session, remove dust with rubber air pear.

Visual use can be successful only at a really good seeing (early morning) and better from a good
unheated place (grassy lawn etc).

BTW. TV Powermate 5x is not very good combination, but you can try.

Good luck!

Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Newly arrived 295mm D-ERF

Post by RaymondTSE » Tue May 30, 2017 5:12 pm

Dear Valery and others,

Thanks for the valuable advice.

I used the DERF to view the (setting) Sun with naked eyes this afternoon. Nice orange colour sky clouds and the red Sun.

It would still take some time before the mating aluminium filter adapter could be tailored-made locally.

The 12.5inch Dob could be used in daytime (for solar watching/imaging on EQ platform through the DERF) and at night (when the DERF is removed).

I would also design a mating adapter to use the large DERF on top of the smaller aperture C925 EdgeHD which I have already owned. Same daytime and night time use as well.

Raymond

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Re: Newly arrived 295mm D-ERF

Post by eroel » Tue May 30, 2017 5:34 pm

Raymond:
Congratulations on your new setup.
Regards,
Eric.

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Re: Newly arrived 295mm D-ERF

Post by marktownley » Sun Jun 04, 2017 2:50 pm

very nice!
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Re: Adapter for newly arrived 295mm D-ERF

Post by RaymondTSE » Sun Jul 02, 2017 5:27 pm

SmartSelectImage_2017-07-03-01-26-36.png
SmartSelectImage_2017-07-03-01-26-36.png (1.23 MiB) Viewed 1046 times
Finally the tailored-made aluminium filter cell adapter for C925EdgeHD arrived. Carefully place 295mmDERF on top of C925HD.
The visual binoviewer setup at F30 is quite heavy now.

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Re: Newly arrived 295mm D-ERF

Post by RaymondTSE » Mon May 20, 2019 2:12 pm

Dear all and Valery,

Some updates when I just start to watch solar images visually recently.

Previously tried to use Powermate 2X on C925HD with Quark Como but F20's light cone was too sharp and thus did not match Quark Combo.

When I switched to Powermate 4X, F40 was too overwhelmed by bad seeing during daytime.

Recently I ordered Baader Telecentric TZ 3X but initial result was also bad for a solar newbie. I then realized the the crayford focuser (about 100mm long) behind C925 was already too long for TZ3X.

I therefore removed the crayford focuser and just re-used C925's original visual back. Adjust focus to roughly 146mm behind C925 so that C925 original focal plan lies somewhere inside TZ3X. Then I placed Quark Combo at about 250mm behind TZ3X ending lens. The final F-ratio was F30 but still magnification was too high even though I use 32mm or 40mm EP.

Yesterday, with a hot weather warning from our local Weather Observatory at 32C ambient, I added a Denkmiere reducer (don't know the reduction ratio but believe it around 0.4x-0.5x), I could finally visually watch a large prominance at about 120-150x magnification. Quark Combo dial position at 1 o'clock.

This is the 1st time I could successfuly watch through Aries 295mm dual band full aperture front D-ERF in front of C925HD. The Big prominance was worth watching. However, no apparent disc feature could be observed, since no sunspot appeared.

In comparision, I also set up original 40mm PST with 32mm TV possl. A very nice 3D red crystal ball but very small.

Next target would be to compare side by side against Lunt 152 L/Ha, may be with a glasspath 2.6x and adjusting to similar magnification.

Raymond Tse
Hong Kong.
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Re: Newly arrived 295mm D-ERF

Post by Valery » Mon May 20, 2019 4:39 pm

Hello Raymond,

Large aperture telescopes need good seeing to realize their advantages in resolution. The common rule is that good seeing much more often can be met early morning, not at hot day time.

So, better if you have eastern horizon open for your telescope.

Hope this helps and I wish you more good seeing. With the seeing less than good, better to use a smaller telescope. Large apertures are mostly for imaging - CCD camera is able to catch the moments of best seeing and then computer find them in the movies, no so with a human eyes. Visual use is more demanded for good seeing.


Regards,

Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Newly arrived 295mm D-ERF

Post by MAURITS » Mon May 20, 2019 7:53 pm

Congrats Raymond.
Regards,
Maurits

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Re: Newly arrived 295mm D-ERF

Post by RaymondTSE » Fri May 24, 2019 3:02 pm

Dear Valery,

Agree that morning seeing is best before the Sun heats up.

My 295mm DERF filter in about 2 years' time has picked up some dusts on the outer surface.

Do you have any recommendations to clean off the dusts in addition to using air blower ?

Suggestions from others are also welcome.

Raymond

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Re: Newly arrived 295mm D-ERF

Post by Valery » Fri May 24, 2019 3:32 pm

RaymondTSE wrote:
Fri May 24, 2019 3:02 pm
Dear Valery,

Agree that morning seeing is best before the Sun heats up.

My 295mm DERF filter in about 2 years' time has picked up some dusts on the outer surface.

Do you have any recommendations to clean off the dusts in addition to using air blower ?

Suggestions from others are also welcome.

Raymond
Air blower is the best. You can use it together with a very soft brush.

BTW. I sent you PM and e-mail.

Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Newly arrived 295mm D-ERF

Post by RaymondTSE » Tue Jun 11, 2019 2:56 pm

While I am configurating the optimum optical train setup for visual solar Ha viewing, I soon find the scorching sun rays hurting my forearms and knees/legs even though I wear hat and neck protection. Further the high ambient temperature of above 32C is no fun for my on-going sweaty face/head.

Then I make a simple sun-shade by putting up a moderate size white drawing board about 40cm wide and 60cm high. Place it over the tripod after the DERF so as not to block the view. Just find a suitable position to block out the irritating sun rays.

A bit more comfort.

Raymond
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Re: Newly arrived 295mm D-ERF

Post by RaymondTSE » Tue Jun 11, 2019 3:06 pm

Another photo.
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Re: Newly arrived 295mm D-ERF

Post by marktownley » Tue Jun 11, 2019 6:51 pm

A creative solution - I like it! 9c here and my central heating has come on this evening. Has anyone told the UK it is summer?
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Re: Newly arrived 295mm D-ERF

Post by Carbon60 » Tue Jun 11, 2019 8:02 pm

Enjoy your new toy, Raymond.

Stu.
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