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PST + DSLR Full disk problem ... AMENDED

Posted: Thu Feb 28, 2019 10:24 am
by solarchatted
AMENDED sizes - Barlow tip is 15mm, not 22mm !
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Hi all
[please remember I am not expert!]

I managed to get a second or third hand PST and I have fixed the play with the tuner by simply adjusting the fitting screw onto the 3rd threaded hole and play is almost zero - even if I have the O-rings, I am not replacing them just yet and I am waiting for a new ITF, as old one has a ring on it!

I also tightened the focuser and shift is a lot less, but for one point where it shifts a lot - will see about that another time!

I managed to take my first image [well 4 images, but processed one only] - I do not have it here and will show it soon.
You can see it here: https://astronomo.space/my-images/the-sun/

I did some testing with Altair 178M, the old ToU cam and they both seem to work decently using only a 15mm 2x Barlow tip onto the cameras nosepiece - I will shorten it a bit too to see if it improves - it should.

I then tried my Canon 100D [modified] and could not get focus - I have read quite a few posts everywhere about it - still cannot solve.

Tried:
- 10mm EOS/T2 + standard nosepiece [22mm] + 15mm 2x Barlow tip - total gap is 37mm, why did not focus?
- 1mm EOS/M42 [not T2 therefore it had a gap of about 4mm] + standard nosepiece [22mm] + 15mm 2x Barlow tip
- 10mm EOS/M48 + M48/1.25" adaptor + 15mm 2x Barlow tip
- Seben Zoom 8-24mm and at around 16-18mm was the best I could go

With/without a IR/UV filter too - to try and less interference.

I do not remember which one was better, but I never saw any surface feature and when overexposed to see Prominences, I did see a couple and I barely managed to get something out with any other above configurations.

I might have tried other configurations, not sure really, as I was getting fed up with it - mainly for the awkward position I have to use my EQ6!

I have got the impression that I need to get DSLR nearer to the nosepiece receptacle and I have also read somewhere, Coronado/Meade did fit two different ones - different by 5mm? Am I wrong? Mine, the nosepiece receptacle is about 30mm and its holder is about the same 30mm, just so you have more info.

What I have not tried yet:

- Meade shorty mod
- Eyepiece Projection should work, I think! I have to find the adaptor.
- ?

Any help guys?

See images of adaptations I used.

IF other things come to mind I will post them.

Thank you in advance for your expertise and help.

M
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ADDITION - amended Barlow tip size from 22mm to 15mm
Therefore with this setting:
10mm EOS/T2 + standard nosepiece [22mm] + 15mm 2x Barlow tip - I had a total of 37mm
I mixed up sizes, but I actually got it right the first time with 37mm, but being my PST 'eyepiece holder' 30mm and not 35mm, I will have to take 7mm off and hopefully work and get down to 30mm.

Going to make it today and hopefully I should get a couple of hours of Sun on Sunday - I mean SUN ... Day - one can hope!

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Re: PST + DSLR Full disk problem ...

Posted: Thu Feb 28, 2019 10:49 am
by bart1805
Hi M,
Maybe your expectations are a bit too high. There is nothing going on at the moment on the surface of the sun. So there is not a lot to image. This is the ideal period to try out different configurations while waiting for more activity.
Nice first picture! Way better than my first one. CS! Bart.

Re: PST + DSLR Full disk problem ...

Posted: Thu Feb 28, 2019 11:03 am
by solarchatted
Hi Bart
Yes, I know it is quiet although yesterday although I saw 3-4 prominences [one arching!] with other cameras.

I am not talking about surface features, but simply DSLR not focusing on granulation and 'barely' focus on prominences - i.e. DSLR is not focusing and other cameras are.

I cannot reach focus on Canon 100D ... yet!
I really would like to see full view without shelling out for 'yet' another camera - not yet anyway.
M

Re: PST + DSLR Full disk problem ...

Posted: Thu Feb 28, 2019 11:16 am
by bart1805
Hi M, have you found this:
http://www.astrosoft.co.uk/Articles/PST ... 20DSLR.pdf
Why would you image with the Canon if you have a Altair 178M. The Altair cam will give you better results.

Re: PST + DSLR Full disk problem ...

Posted: Thu Feb 28, 2019 12:44 pm
by solarchatted
Hi
Yes, I read that 'nice PDF' and it it is one of the things I could not try yet - because I do not have a Shorty.

Therefore I used a 22mm Barlow tip and stupiditely forgot about the 35mm eyepiece holder he had and also mine is 30mm - so I need to reach 30mm.

I think I am getting it now - I forgot that bit, thanks to re-directing me back there to re-read it.

First I was at 52mm - 22 off, then 43 - 13mm off then 23 - 7mm LESS - this probably was the nearest I got to focus, when I saw some prominences.

I can try shortening a nosepiece by 22mm [being 30mm in total - I need to measure it and I should be OK or get a short nosepiece.

It costs less to shorten normal nosepiece, also you can slowly file it until you reach best focus - one hopes!

I have to see what bits I have at home .

The only reason I wish to use the DSLR is to be able to easily take the whole disk.

The 178M seems to get about 75-80% of the disk with 30mm nosepiece + 22mm Barlow [52mm].
I am now hoping to try the shorten nosepiece [as above] from 30mm to 8mm +22mm Barlow [30mm total] onto the 178M as well and get the full Sun?

Unless I got it wrong again.

... I am not sure ... the 2x Barlow tip I have is quite thick - 22mm - compared to the shorty and possibly is focal length is different and the 30mm 'rule' is not valid - well, I can only try.

I even put the Barlow tip inside the eyepiece holder and played manually by adjusting camera in-out - no change!

M

Re: PST + DSLR Full disk problem ...

Posted: Thu Feb 28, 2019 3:59 pm
by skyhawk
I had a PST and needed a barlow to get focus

Re: PST + DSLR Full disk problem ...

Posted: Thu Feb 28, 2019 8:27 pm
by marktownley
Personally, I wouldn't waste time trying to image in Ha using a DSLR results are mediocre at best. You need a short c-mount nosepiece https://www.ebay.co.uk/itm/Short-C-Moun ... :rk:2:pf:0 and a barlow nosepiece and use the 178M.

Re: PST + DSLR Full disk problem ...

Posted: Fri Mar 01, 2019 8:35 am
by Sol seeker uk
Whilst on the subject of camera's, I'm finding it difficult to find focus on my Skyris.. would one of these c adapters work? I've no idea if I'm looking for inward or outward travel..tried a 3x Barlow(Not on the nosecone as it won't fit)
If I do need to go down the new camera route am I right in thinking smaller pixels on a standard pst, and does that change if I stage 1 or 2 mod it? Was looking at the qhy5 290m

Re: PST + DSLR Full disk problem ...

Posted: Fri Mar 01, 2019 10:27 am
by solarchatted
marktownley wrote: Thu Feb 28, 2019 8:27 pm Personally, I wouldn't waste time trying to image in Ha using a DSLR results are mediocre at best. You need a short c-mount nosepiece https://www.ebay.co.uk/itm/Short-C-Moun ... :rk:2:pf:0 and a barlow nosepiece and use the 178M.
Hi
Just finished cutting/filing the nosepiece and with barlow fit I now got a 29mm total.

I understand what you mean now - therefore by nearing the barlow towards the 178M I should get a full Sun image.

OK, I can try use the one I cut now ... for now.

Thanks
M

Re: PST + DSLR Full disk problem ... AMENDED

Posted: Fri Mar 01, 2019 11:33 am
by solarchatted
If you can buy a new one, it seems the 174M is top with the PST!
I am only using the 178M, because I own one and save me to spend more than I have.

Which Skyris Model do you have exactly?
I am no expert, but I might be able to help and in any case you need to add that Barlow Nosepiece [the tip of the whole Barlow] and the C adaptor as mentioned by the very helpful marktownley or make one yourself.

Re: PST + DSLR Full disk problem ... AMENDED

Posted: Fri Mar 01, 2019 11:43 am
by marktownley
The pixels on your 178m are much better suited than the pixels on a 174m - 174m much better suited to longer focal ratios.

Re: PST + DSLR Full disk problem ... AMENDED

Posted: Sat Mar 02, 2019 10:58 am
by solarchatted
marktownley wrote: Fri Mar 01, 2019 11:43 am The pixels on your 178m are much better suited than the pixels on a 174m - 174m much better suited to longer focal ratios.
Got it - thanks.

I could have brought my PST to work this morning as SUN is very clear - idiot me - to test the adaptor with DSLR and 178M
Hope tomorrow morning is decent enough ...

Re: PST + DSLR Full disk problem ... AMENDED

Posted: Sat Mar 02, 2019 12:50 pm
by Sol seeker uk
Which Skyris Model do you have exactly?
I am no expert, but I might be able to help and in any case you need to add that Barlow Nosepiece [the tip of the whole Barlow] and the C adaptor as mentioned by the very helpful marktownley or make one yourself.
Thanks..I have the 236m Skyris and have bought one of those c adapters as they was cheap enough so if it don't work it's no big loss and maybe use it for something else.