alan potts

15 hours ago, symmetal said:

Yes, no problem Alan  Hopefully your focus lock has improved things.

Alan

I never realised that F4.3 even on a refractor was so difficult, the tiniest bit out seems like a mile. Judging by the blurred shot from the other night stars at least look round and seems to have lost that redness. Maybe the L2 filter will do the job which is the same one I had in place when using the scope with the 071mc , the results from that couple of weeks were much better but the FOV is much larger, however there was still that mis-shaping at the edges which was before I got the correct spacer tube, 1mm seems to make a massive difference.

11 hours ago, Skipper Billy said:

Ditto - fire away

 

Now all we need is the clear skies I have had for past week, looks like the weather has taken a down turn which with the Moon getting bigger is a good thing I guess. Soon as I get something I will post it here, thank you both of you for what you have done.

Alan

Never seen that before, a lovely capture there in my opinion and low for you, I'm about 11-12 degrees better off so maybe one for me to have a go at.

Alan

2 hours ago, astro mick said:

Thanks Wim,i will try that on my next bright star target.

 Cheers Alan.

Just thinking out aloud.I thought for the amount of time pent on this,i would have achieved a better result.

I,ll still plod on.

Mick.

Feel we all feel like that from time to time. I was trying real hard last night to put something right after receiving good advice from some members on where I had gone wrong, as a result I found the problem, a focus locking knob that I could not see and had forgotten about. So in my hast to grab a patch of sky banged off 14 x 3mins, and made an utter mess of the focus. Back to the drawing board, I think even though it is not sharp though, I am on the right track to put things right. There is so much to remember with this damn hobby.

Alan

One for me to avoid if it's that faint, I get fed up in the patch of sky after 2 hours tops, it's a very nice subtle nebula that you have captured and one I have not seen done before. I think you have done grand, don't pack it in I enjoy your captures.

Alan

11 hours ago, Skipper Billy said:

Well I have learnt something there!

11 hours ago, symmetal said:

Actually, thinking again, the CCDI results could be seen as more useful  with OSC in that they do show where your focus problems are for each colour which you couldn't do if it was a mono camera with a Luminance filter. This would just give effectively the composite image as Billy posted and you may try correcting tilt etc. when it's seems to be primarily a Red focus problem.

Alan

Look if it is OK, Dave and Alan, thanks for effort you both have put in, can I post a tiff for you both (maybe here and message you both) where I have now tighten up the focus lock, this clearly and visually had an effect on the plain of the rear part of the reducer. My feelings are this could well be causing the lions share of any problems. Though it is not so easy to see changes on my screen stars did look round again, though maybe still not the sharp focus that it could be (maybe this is the filter's weakness causing this)

I did get out last night to try things but the gap in the clouds was small and I rushed things and got poor focus, it was good enough however to see there was a dramatic improvement in star shape and general colour. I don't think the Tiff file would be good enough for the same treatment that you put the other file through but will upload if you wish, it is only 14x3mins so not wonderful.

What happened was where I sit in the obsey I cannot see this knob which locks everything up nice and tight, also straightens things up. I simply forgot about it the last few weeks and this is when results have been poor, I have to say the same problem was not so obvious when I used the 071. I will also consider the L3 filter at a later date when I am hoping to buy one of FLO new apo's, maybe the 85mm.

Alan

6 minutes ago, vlaiv said:

That Borg is rather fast at F/4.3 and even triplet would struggle with color correction at that F/ratio so no wonder that double shows a bit of unfocused light. L3 could help, but not sure how much.

In any case - this is one of the reasons you are struggling with focus - fast scopes have very thin critical focus zone and it is rather hard to get good focus - although your image seems to have that aspect covered, I have not seen any focus issues (even in fast dropping temperatures).

The time I try to take to get focus is unreal, I see now just how tiny the sweet spot is. I may well invest in another filter, can't believe I bought two the same how daft. The L2 works fine on the 805mm apo but then that's F7 and decent quality so maybe should. I really value your input, don't always understand it all but I always read your posts.

Alan

27 minutes ago, symmetal said:

Looking at the individual colour channels the red is significantly out of focus over the whole image compared to the green and blue. The green shows the best focus with the blue almost as good. Also on the right side of the image the green and blue channels are still pretty good with the elongated stars being caused by the red channel. As it's a OSC camera it would seem to be too much IR getting through. The L2 Astronomic filter has a wider passband compared to the L1 and may not be so suitable for this scope but I'm surprised it's causing this much blur on the red channel. 

Alan

Maybe I was seduced by it being a Borg scope, which I was of the opinion was a quality objective even though it is only an ED 2 element. L1 is for the highest end scopes I believe so I think you mean L3, which ever way I can check. I have found something else I was not doing by way of tighening the focus lock, this lifts the camera slightly from the free-focus position, I dare say this will have had an effect.

Alan

11 minutes ago, vlaiv said:

I was under the impression that it is other way around L1 being widest and L3 narrowest of the three:

In any case this scope would benefit from the narrowest of the three (L3 according to above graph).

I only have 2xL2 which when I think about was a bit stupid, this is a Borg so should be a quality objective, L1 is for high end APO's like Tak's etc I settled for the middle ground. Thanks for the help read the last post of mine in answer to Carole, something I missed.

Alan

1 hour ago, carastro said:

I just processed it.  

It does look like something is going on in the corners on the right side but not the left (In the orientation of the download and my process.

As the left side top seems OK to me and the bottom left OK (ish), I would suggest this is probably tilt though there could be another factor involved which I can;t quite fathom since the stars are elongated upright on the top right, but diagonally bottom right.

 

Carole, Skipper and Vliav,

Don't feel you realise how much I depend on you lot and what a help you all are to me. Thanks for all you do, I always take what you say seriously, even if it looks like I don't. Carole you image looks so much better and very much like the one I got got second go, lord knows what I did with the one I posted

Confessions time, I have just notice a shinny chrome knob on the tube of the scope near to the focus, yes if I am honest I have seen it before but sort of forgot about it completely. When you tighten this it does move the back part of the tube a couple of millimeters or so which is sagging with the weight of the camera and cables. After tighten. post focus I have to say the stars look so much better and pretty much round, its difficult to tell on the readouts from APT but look OK. I still find this helical focus system a difficult one to use, or is it just APT making it difficult as I only get an image every second.

I think crabby processing aside you have helped me find my answers.  With the clear skies I get I should be telling you lot how to do things I get so much time outside, maybe one day.

Thanks all,

Alan

Alan

Yes I did not pay too much attention to the processing and actually (wrongly it seems) though I was helping. I post here the tiff right out of DSS just reduced to 16 bit so it loads this week.

Vlaiv, I am using a L2 Astronmiks IR/UV filter which normally gives decent results on my APO but this is only an 77EDll two element Borg.

M43 32x 3mins 183mc.tif

Many thanks both of you.

Alan

I posted up an image before but didn't really get any feed back as to my problems. The 183MC or 071MC are correctly space at 37.5mm back focus on this scope, I have bought the correct spacers now.

Could the more knowledgeable on site have a look at the stars and tell me if they think it's,

1,  Guiding, the air was a bit turbulent last night as it was 21c and quickly dropped to 6c over the image time of 2 hours.

2, Spacing, if so too short or too long.

3, Poor focus, I still find it very hard to focus this scope, even though I really take my time, the sweet spot in so tiny.

This is 32x3min subs with Darks and flats at minus 5 with a 183MC on a 330mm Borg F4.3 scope driven by CEM 60 with SW ED guidescope and 290mini..

I realise it is not well processed and over sharpened but I did this purely to get help and hopefully highlight the problem area.

Many thanks,

Alan

That's amazing when it is obvious how small it is judged against the nearby star, think I need one of those telescopes you have, now how do I tell the wife.

Alan

Different that is for sure, I rather like it. Did this last night but the result was poor, I don't know if it is the spacing still not exact with the Borg or just awful guiding, the weather was 21c yesterday and it dropped away very quickly once dark.

Alan 

I always find M1 a bit of a disappointment at my focal lengths, so far up to 805mm, at least you have about a meter but it will still be small I would have thought, I did M78 the other night with a 330mm Borg and 183mc camera and it came out reasonable at 90mins with 3min subs at F4.3, so your a tad faster. I would have though assuming all subs are usable the M78 would be better.

Alan

That's nice Brian, I will be able to try it myself soon, Obsey roof and house get a bit in the way, need the longer scope back on the mount too.

Alan

I can only imagine a person that puts out a whole load of really good images is just about to go to another level. Good luck, I know with new gear like this it is needed and I hope everything runs smoothly. I expect you will have bad weather now stopping me seeing your work.

Alan

Beautiful image, one I will try myself now I know where it is, all these different names and numbers very confusing for the likes of me.

Alan

Very nice images Goran, must try the bubble again. BTW did you ever try out the PEC on the Eqmod and mount we were talking about before the sun became a pest to you up there in far north. Based on a good run with it before I bought the CEM60 I think it did help.

Alan

Beautiful image there Dave, I was say that is as good as i have seen, you have done yourself proud. The framing is very nice too.

Alan

I image this the other month and got a very similar result, difference being, I didn't know what I was imaging until the processing started. Nice shot of it you have taken too.

Alan

Worthy winner as I see it, stunning image, and I don't like the Moon that much.

Alan

Ha ha, I actually did this the other night with the Borg at 330mm and got everything around about as well, can't see anything of detail your lovely images show, must try the 805mm on the same target in the next few days though I only have OSC to throw at it.

Alan

Both very nice images, now I must find out where it is.

Alan

A very nice image there, lots of detail and a wonderful result for only 48 mins.

Alan

Very nice shot indeed.

Alan