Clarkey

I must confess it does not look too bad to me. However, I am using a laptop with a rubbish screen. From what I can see, all the stars seem to elongated the same way (top left to bottom right). If they are all the same this certainly suggests tilt. If you are seeing it on more than one camera it may be the focuser is slightly misaligned? Always worth checking. Alternately, if you are using the same T-ring for both camera's it could be this?

Nice image. Was this with a flattener?

There is a thread on the FLO area which includes images from the SM90. I have one and I have been really impressed with it. I'm still trying to get a completely flat field with the flattener (not the 0.8x which is fine, but the 100%), but that is not a fault of the scope.

I did a comparison last night between M53 with the SM90 and my StellaLyra RC8. Once processed there was very little difference which is pretty impressive when you look at the FL.'s of 540mm and 1600mm respectively. Yes I am oversampling on the RC8, but once scaled similarly you can not see a lot of difference.

These days the bulk of LP is LED and general filters have limited benefit. Unless doing narrowband I would not bother.

I would say keep your subs short and take lots of them.

Good luck.

3 hours ago, Daf1983 said:

but struggled to get much colour out of the data

Did you use any filters? This will reduce the spectrum available. (From M82 I would say not, but it would depend on the processing).

39 minutes ago, ONIKKINEN said:

My mantra on galaxy imaging is that broadband filters have too many negatives to be of any decent use and i dont see how one would be useful, unless in awful conditions (Bortle 8 maybe)

I'm with Onikkinen on this. I try to avoid filters (except for narrowband) and collect as much data a possible then deal with the gradients in processing. Use more shorter subs and get a better S/N ratio. I image in Bortle 5/6 and don't use LP filters. If I lived in a city centre I might feel differently......

20 minutes ago, iapa said:

These 2 guys know more than the other 99% of us

I think you meant to say they know 99% more than the rest of us😂. Or maybe it's just me......

Vlaiv is certainly a SGL legend. Not only knowledgeable, but more than willing to share that knowledge. I have certainly learnt more from Vlaivs posts than anyone else.

On 18/03/2022 at 10:28, powerlord said:

Has anyone seen @vlaiv and @ONIKKINEN in the same room ? Are they twins seperated at birth ? I think we should be told.

I believe the Finish language has its roots in the Slavic dialect. You might be right.

Either that or they are just more nerdy (and clever) than the rest of us.😀

Why it  would work intermittently is a bit of a mystery. The only think I would try is making sure all your drivers and software are fully up to date. I can't really think of anything else... Possibly a cable issue?

Firstly, for wide field imaging the pixel ratio is fine. Yes with good seeing you might go higher but you won't gain much.

One hour is not a lot of integration time and getting much more will improve the quality. I think most of your pixellation is actually noise. As a rule I never image more than 1 target per night and usually a minimum of 4 hours.

I don't really do much OSC so not really the best person to help on this. I also avoid LP filters. As a rule I would rather collect all the photons I can and remove gradients in processing.

FWIW I have the GSO (TS) F4 150mm and I have had to do quite a bit to get it up to imaging standard. Optically it is OK but tricky to collimate. The main negatives were the focuser was simply not good enough and also the cost of the F4 coma corrector. I tried the Baader MPCC as I already had one but this gave poor stars at the edges of the 1600mm pro. Additionally I have had major problems with reflections from the filters. I will try it with a DSLR to see if it is better, but it may not be. The other issue is trying to get the balance right - it took a lot of adjustment to get it right.

If I was to go down this route again I would buy the F5 or something completely different. (I did - I got a Stellamira 90mm ED triplet).

On 21/03/2022 at 12:25, PatrickO said:

Does anyone know if this is a good intervalometer?

I purchased a similar wireless one. Has the advantage that you don't disturb the scope whilst imaging. Also less wires.

I've got to agree with the other posts. For that budget you are better off staying with your DSLR. If you only use it for astro you could pay to get it modified so it will be better for Ha rich targets. The other alternative is to buy a modded DSLR. They regularly come up second hand for around £200. I have a mono camera, but I still use the DSLR as a OSC.

Don't worry we all do daft things. Last night I could not believe how good my guiding was...

Today I set everything up again and realised I had been using the calibration for an OAG at 1600mm FL, not the 400mm FL guidescope. Moral of this story - if it looks to good to be true, it probably is!

10 hours ago, ollypenrice said:

Edit: Crossed with Clarkey above. I plugged your scope, the ZWO 294 and a 0.7x focal reducer into the calculator in the link. It looks as if you would need a 4 panel mosaic to image M42. That is very limiting... However, check my findings.

No you are right. I was thinking more in terms of galaxies etc. If you want wide field I think it's probably the wrong scope. Even with a larger sensor the field of view will still be relatively small.

On 18/03/2022 at 11:16, fwm891 said:

Must try again on a clear moonless night (some hopes!)

I'm hoping for this at the end of the week. Forecast is promising and seeing tonight looks very good.🤞

You've picked up some of the nebula detail which is tricky on this target. I might have to give it a go with the RC sometime, especially now it is well collimated (with your help).

Hey, I'm just pleased when someone suggests I have an idea of what I am talking about🤣

13 hours ago, Mike Q said:

The key to collimating with a laser is to make sure that the laser is properly aligned first.

Agreed. A lot of the cheap collimators are out by quite a margin. However, most of them you can clean the 'gunk' out of the 3 collimating holes and get them accurately aligned. I made a jig out of lego to test mine against a wall 10m away.

First decision you need to make is whether you want colour or mono. There are loads of posts on this subject which you can read if you have time! Similarly there are lots of 'first camera' posts - so worth doing a search for some general info.

Looking at the budget, I would say you are probably looking at OSC and second hand. I think you really want to have set point cooling for an astro camera which makes it possible to have a pre-made dark library.

In terms of specific camera, if you are using a 0.85 reducer flattener for the ED120 something like the 294mc pro would give you a pixel scale of 1.12 which would be OK. Most cameras have very small pixels so you make have to bin with anything smaller. Have a look at the astronomy tools CCD calculator and try different cameras. You will want a pixel scale of 1" to 1.5"/pixel, or even a bit higher.

With the mount and guide scope you have guiding should not be a problem to level you need for the FL of your scope.

If you look on the technical specifications on the ZWO website it states the 2600mc has a IR D60-2 cut off filter. This is at 700nm so should still pick up Ha. I think a lot of cameras cut off a bit earlier.

Protect window: D60-2 IR Cut

I think there are definite benefits to both - an plenty of threads on/SGL about the subject. I have mono and colour (DSLR), and my next camera will be a OSC astro camera of some type. However, I would not be without the flexibility of the mono camera. For your budget it will also depend what sensor size you want.

Mono is certainly not 4x the work assuming you have a EFW, and yes, the images are better in theory. However, with UK weather being a fickle as it is OSC does have some advantages. I have quite a few sessions of part filled LRGB as unexpected clouds have ruined the party. If this was OSC I would at least have an image. Having said this, I also like narrowband imaging, especially around the full moon. With the exception of dual / triple band filters this is not really possible with OSC.

Ultimately, either choice will give you decent images. If you like simple set up then OSC may suit, if you want to do NB then I would go with mono.

14 minutes ago, vlaiv said:

That doughnut is not perfectly concentric

You obviously have better eyes than me🤪

Certainly looks pretty close to me.

Now for some galaxy hunting......

I live in B5 or 6 and I don't use any filters except for narrowband. I would rather get all the photons and sort out gradients in processing. If you have specific issues with sodium or mercury vapour lights there may be some benefit, but if the bulk of the lighting is LED I'm not sure of the value.

Looks good but clearly not enough wires🤣

I'll add another one to the party....

Also taken on the 5th and 6th of March with the StellaMira 90mm ED triplet on an HEQ5 Pro. Imaged using a Canon 600D with no filters over about 13 hours with around 12 hours usable data. Bortle 5/6 garden and the seeing was not very good. Processed in Astro Pixel Processor, Startools and Affinity.

Main spiral galaxy is NGC4535 'The Lost Galaxy of Copeland', below that is NGC4526 'The Hairy Eyebrow'. The other main large galaxy in the picture is M49. In addtion there are a number of smaller galaxies including NGC4469, NGC4519 and NGC4460 all within Virgo.

NGC4535_Group-ST2 Crop.tiff