swag72

I have just got an IDAS as a replacement for my luminance filter. I did a comparison a while back of a 300s sub with the IDAS and without. The general consensus was that the contrast was better with the IDAS. It may cause a colour cast, but nothing that can't be easily fixed in post processing.

This is a good service. I recently had to have an adaptor made, but got given another contact - At the time it was very frustrating to not be able to find what I needed.

I use the method that Chris suggests and it works well. After the first manual clutch adjustment, the next lot of alignment stars are very close to the centre. I also make sure that I do alignment stars near to or around the target. Then using CdC (if it's too faint on the camera chip) I can work out star patterns to get it bang on where I want it in the frame.

I've had a runtime error before and sorted it as per this thread http://stargazerslounge.com/topic/127307-eqmod-runtime-error/page__hl__+eqmod%20+runtime%20+error#entry1265365

I have a Moonlite focuser on my refractor, but haven't tried an Optec. My thoughts on the Moonlite are that it is a well engineered piece of kit, works well and holds a load without any problems. I love it.

.....But ....... Having a scope with a quality R&P as standard, this is better to use than the Moonlight, so as above, I would recommend that you at least look at a Feathertouch. You really can not go wrong with them.

Determining how far from the target my guidestar is could be interesting!!

So, I'll wait and see what the all in one finder guider comes up with and see if it's better with that! I do hope so as I was able to routinely get 20 min subs with no guiding issues. So I know my setup can do it, just not at the moment!!

I think I know what my guiding issue is but does this sound right to you ............

.......... Ever since moving my guider to the saddle on the left of the focuser (I've got 2) it's got worse. I think that the guider is pointing WAY off from the scope. That is why when I get my finder guider package, where the finder will be aligned to the scope, and so the guider will too, my issues will probably improve.

I know I could just move the guider back to the right hand saddle, but then I can't use my finder as my filter wheel is at a funny angle!

My scope is at 900mm.

I have some potential issues that I am trying to sort and so will carry on in thi sthread as it is relevant and may help later down the line.

I have great 3s subs and nice round stars. When I get to 300s subs, I have awful eggy stars, but predominantly on the right hand side of the image. I know that it's not focuser alignment issues though as at 3s it's all fine.

So, in my frustration with it all, all my 300s subs are deleted!! But I did have 4 x 60s subs left. I put them through DSS as per the tutorial linked by Tim earlier in the thread and have the following DSS output screen.

How can I determine anything from this? In order to determine drift I need to divide the number of pixels by the drift figure (Dy and Dx) - How do I know the number of pixels? I was using my 314L.

Excellent explanation - At the 30min stage I have non uniform egginess - So rotation more than likely. What can you do to eliminate field rotation? I use a finder / guider which is not moveable in guiderings or anything, so quite where it's pointing I have no idea!! I though that 'in the general direction' was good enough, but clearly not.

So, ways to help combat field rotation? I have recently checked my polar alignment with the EQMOD polar align tool, so I am quite happy that this is pretty spot on. Is there anything else that can be done apart from just PA?

Cheers all, very useful info there.

Cheers Tim, I'll look at that.

I just assumed that flexure would show up well before the 30 minute stage and so I'd be having problems at the 20 minute sub stage, but they are OK.

I am routinely getting 20 minute subs, with round stars and no problems. When I tried 30 min subs a while ago, the stars all got rather eggy. At the time I thought maybe that was down to flexure.

My question is whether, if it was flexure, it would be showing itself in the shorter 20 min subs as well? In which case I think I may benefit from a drift align.

I would welcome your comments on this - Would flexure be showing up with the shorter 20 min subs as well?

Glad that you got to the bottom of it. Was it easy to do? Also, what grease do you use? Is there specific stuff to use for the mounts?

FLO are excellent - They take time with you answering questions and giving advice. I ordered an Equinox 66 from them and they shipped it out to Spain with no problems. It even arrived a day earlier than the Fedex estimate. A big 'hurrah' for FLO from me!

I have an Evostar 120ED and a Canon 1000D - Planets with this setup are pretty dire, not much bigger than a pin head. Regarding nebula, how about uploading the free software Stellarium and you will be able to put in your coordinates, time etc and it will show you what you can see and where.

Anpther good place to look I always think is Flickr. If you put in the 120ED into the search window, I bet there's loads on there to look at.

Hope that helps.

Worth a try then sometime I reckon. How does making an image greyscale improve the overall image when you have layered it back in? I presume that you would use layers to get the 'luminance' back into the image? And just overlay it at an acceptable percentage?

Ahh, OK. As you know I do like to think about what is possible with OSC camera's and have asked a couple of similar and probably rather naive questions as I try to understand how I can improve my DSLR images, as I want them to be the best I can possibly get.

I too was probably confused with NB imaging, thinking that luminance was somehow similar to Ha capture. I didn't realise how intrinsic it is to the whole colour image as a whole when taken with OSC. I though that maybe it could be seperated out somehow to improve OSC images.

Well, it's back to the brain farts for me then!! Until I have another .............. Adios!!!!

What would you get if you put a luminance filter over the front of a OSC?

I read that Luminance is most important when using a mono camera, while the RGB stuff is just to overlay some colour into the luminance channel.

Can you then get luminance using a filter and a OSC camera? Maybe it is the same principle as Ha, where you are only really capturing 1/4 of the data due to the bayer matrix? But you can capture it nonetheless.

Just one of my off the wall thoughts!!

I know that I joined a year ago, but only opened my telescope a couple of weeks ago!! So I consider myself very new to all of this, despite my welcome post being almost 12 months ago!

The folks on here have been brilliant. They are really understanding and helpful with my stupid and dumb questions!! Probably ones that the have heard countless times before! A couple of members have responded to my PM's when I have a specific question for them - All in all, this is a great place with excellent people on here.

Thank you to all, and I look forward to being able to put something back into the forum, instead of take, take, take, when I know some more!! Thanks SGL.

Here is my very first image and DSO last week - M45. This was taken on the second or third outing with my 5D2, Skywatcher 120ED and HEQ5 mount. I've had the setup for about 8 months, but only recently plucked up the courage to try the polar alignment etc. This was a number of subs at 45s I think and a couple of darks. With what I have learned about processing in the last week, I will go back and look at it again at some stage, but for the moment, here it is ............

The Pleiades - M45 by swag72, on Flickr