Clarkey

As @The Lazy Astronomer says, in Bortle 7 the read noise will be swamped in seconds. In reality you just need to choose a sub length that allows you to take enough total integration time without needing a super-computer to process. Personally, in my B6 back garden, I use 2 minute subs for most targets and 3-5 minutes for NB.

Have you watched the Robin Glover video about AP. Well worth a look if you haven't.

Right now it does not matter. Clouds look the same through all the scopes!

If I was to limit it to one, it would be the 115mm triplet as it is the most versatile. It is a good imaging scope but also very good for visual. Can I use the ST80 as a guide / finder scope?😄

The AZ GTi will mount up to 5kg and is probably OK for visual with a decent tripod. The are other options depending on your budget.

Having seen these lists I feel much better.

And I can justify a new one. Yippee!!

Let's just hope the current weather is a 'blip'. Good luck with the Spanish imaging. RASA to 17" CDK - on extreme to the other!

I think it is a really good rendition. Different with the exaggerated Ha - but in a good way. I particularly like the first one.

That's a great image. Really nice detail.

I spent a night imaging with my RC8 and 115mm triplet (total of 18 hours) and got nowhere near this amount of detail. Admittedly Bortle 6 with pretty poor seeing.

I do need to check though Göran, are you sure you live in Sweden? You get more clear nights than my Spanish and UK rigs put together! I think you have a direct link to Hubble🤣🤣

10 hours ago, TiffsAndAstro said:

it will be cloudy here for the next 8 months

Only 8?

You could learn Pixinsight. That should take about 8 months 😄

On 09/03/2024 at 18:58, Stuart1971 said:

Well for anyone looking for the superb IMX533 mono sensor, check this out, works out at £400 on Amazon with the 45% off vouchers

I looked at this and gave it some serious consideration. However, doing a bit more research there does seem to be a banding issue with the Svbony version of the 533. I can't comment from personal experience, but I believe there is a thread somewhere of SGL about it.

I certainly agree regards the meagre pickings. I have managed 5 hours in the last 6 weeks😫

3 minutes ago, AstroRookie said:

As for "flex between the guide scope and the scope image", I'm sorry but I don't really understand (my native language isn't English)

If the image in the main camera and the guide camera are changing relative to each other due to movement of mirror / focuser / guide scope - 'flex'.

Your English is certainly better than my attempt at any European languages. Smattering of French is my limit - much to my shame.

9 minutes ago, AstroRookie said:

also the PHD2 graph looks fine to me

If there is any flex between the guide scope image and the scope image the guide graph would be irrelevant. However, if 5 second exposures are also showing poor star shapes the culprit appears to be the optical train. Have you tried rotating the camera and coma corrector to see if the aberration follows?

I'm not trying to be patronising - just trying to rule out the obvious.

Have you tried some short exposures and looked at the shape of the stars? If they are round it shows it is not an opitcal issue, but probably a guiding related problem. Are you using an OAG or guidescope?

Edit - probably unrelated, but your focus curve is very odd...

My method is very different. If you are talking about the Adam Block videos, this suggests you use PI for processing?

For my (acceptable) comet image, I used a very different process.

1. Take the normal shots and then remove the stars from all the images using a batch process in PI. (This takes a long time)

2. Comet stack the starless images to give the comet stack. This will have some minor trails from where the stars were removed.

3. Process the comet image using masks etc to blur the star trails that remain.

4, Run a normal star stack to give you the star image. Remove the stars and add them back to the comet image as per normal processing.

There may be a better way - but as yet I have only paid for the Adam Block Fundamentals videos. The comet and Horizons is more expense....

Below is the result. (This was about the first image I had ever done in PI, so I suspect I could get better results now I know what I am doing with the software).

Very nice rendition. The good seeing certainly helped - very crisp.

This was one of the first galaxies I ever imaged back in the days of my 600D. Looking at my version makes me realise I need to do it again!

Most astro gear likes a bit more than 12V so it will be fine. My '12V' supply is 13.8V and it runs all my kit without any problem. I'm not sure how fussy the Air is, but my mini PCs are rated from 12 - 19V so I doubt it will hurt it.

I did this a couple of months ago, with the data courtesy of Roboscopes in Spain. Using a 12" F3.8 newtonian with a ZWO 2600MM pro. This is about 26 hours of LRGB in total integration time. Processed in PI. It has been quite humid and there is quite a bit of IFN in the region - the two together made the processing challenging to get the detail. After a few efforts I have managed to come up with something I am fairly happy with.

Constructive criticism and comment welcome as always. 

Have you tried running the EAF through the hub and the filter wheel directly through the ASIAir? In theory it shouldn't matter, but it is worth a try. If the EAF is causing the problem with the air, this might prevent it?

I have similar problems to this in the past and I appreciate how frustrating it can be. Even though I never managed to get the root cause sorted, by changing ports or cables etc, would normally cure the issue eventually.

I managed to get this by cropping to a rectangle and running through DBE in PI. I suspect it would give a better result without a the JPEG compression. I would also suggest Astro Pixel Processor. Unfortunately, my licence has expired so I could not try it.

I have made nichrome dew heaters and although they are effective, for a small lens heater I would still suggest the resistor option. Nichrome is a pain to solder effectively and quite expensive to buy for a single use. Of course, it will work.

You could make one from a ring of resistors in a sleeve. That's how I have made a couple of mine for secondary mirrors. Plenty of guides on line.

The first quote was in the link I sent above.

With regards to the fringe killer, it will help as it takes out the blue wavelengths - normally to reduce chromatic aberration. However, this is really an observing filter so will mess up the white balance. Also, you need to be sure it is only reflecting in the blue channel. If it in the other channels too, then the fringe killer may not work. If you take one of the images above and separate the RGB channels using and standard editing software, you will be able to see if the blue removal works. It is worth noting that if it is only on one channel, it is possible to remove the reflection by editing one channel only by copying a section of one of the other channels over the reflection. When you recombine it should give a reflection free image.

Edit: I have just looked at the first image and the reflection seems to be in R,G and B so the fringe killer probably will not work.

I was just wondering whether a good quality uv/ir cut filter with an anti reflection coating might help. Something like an Astonomik L1 or similar. Bit of a long shot but might help.

Another option maybe to introduce a small amount of tilt into the scope. Just enough to stop a direct reflection back to the corrector plate. Not ideal, but slightly imperfect stars maybe better than the reflection?

Found this that references the problem as a known issue:

Schmidt Newtonian for astrophotography? - IceInSpace

Maybe a non-reflective filter would help prevent the ghosting?

Is there anything else in the imaging train? Filters or something?