souls33k3r

8 hours ago, Davey-T said:

All other things being equal its worth remembering given the file size of bigger sensor CMOS cameras that a 300sec' and 600sec' sub have the same file size.

Dave

Absolutely but truth be told, the file size has never really bothered me much, only because I've not known a life in astrophotography with a smaller file size. I remember seeing Alex's face when he asked me the file size of my camera because he's used to around 1MB of a file size 😂 

What does bother me is the 294MM file size 47MB (bin 2x2) and 97MB (bin1) and I suppose the 2600MM is going to be even more crazy 😁

I've always been in the 300s sub exposure with unity gain kinda guy. I could've used the SharpCap smart assistance or whatever that tool is or use Robins formula. I was in a bit of a rush so got a mate of mine to punch in some numbers using my F/5.5 in Bortle 8 skies and that came out to be 245s so using 300s subs, I wasn't too far off. But there was this itch I just had to scratch so I went with a 600s sub. Tbh I can see so much more nebulosity with a 600s sub (of course it's double to that of a single 300s sub) but when I have that mate 2x300s subs and compare that against a single 600s sub, the stars were just a tad bit bigger but only if you're pixel peeping, noise was almost the same tbh (single subs show the single 600s sub having less noise) but the Signal was evidently better. 

I might start doing 600s subs from now on and like you said there's always that risk of risk of losing a sub because of whatever reason but truth be told I've hardly ever discarded a sub because of my gear, more to do with clouds. 

Hope this helps matey. 

A true master at work. Beautifully done Peter. 

Very nice indeed. The Antlia weren't supposed to give halos as they made a big thing about that on Facebook. 

Also, your stars do look off, more like pinched optics to me. Maybe someone else with a bit more knowledge and better eye can chime in. 

I'd be very interested in this as well.

I live in London myself (Zone 4 - East) and L-eXtreme will give you a 7nm bandpass in Ha and OIII which will be far effective than trying to use the 294 as an OSC from Zone 3. Galaxies are RGB targets with a hint of Ha for which you will most definitely need some kind of a LP filter (I'm not too clued up on that side of things) but my answer was. Specifically aimed towards you wanting to use Ha filter with this camera. 

I'm truly sorry to hear the troubles you've been through but it's good to have you back and feeling better. 

Optolong L-eXtreme filter is a much better bet which works on Ha and OIII at a generous bandpass. 

An absolute pukka image Geof. 

25 minutes ago, Spongey said:

Not sure if this was resolved for you but I've been reading this thread on CN and it might be of interest to you.

The whole thread is worth reading for background info but in particular posts #276 and #278 detail the problem you're having and the potential cause (in short, this is not caused by the filters and is instead due to centrally obstructed optics producing an extended airy disk which is being detected by the camera).

Thank you for the link mate. Unfortunately I haven't had the chance to test anything since I last posted because of the spell of bad weather we've been going through. I do however plan to test this with another scope on the next clear night which who knows when is coming. I'd be sure to update this thread with the findings. 

35 minutes ago, johninderby said:

More non astro. A monotor for the exercise bike that arrived the other day. Now I can see where I’m going. 😁

To FLO and back I presume to pick up your new telescope. Don't you worry, your secret is safe with us mate

One of the best images of Andromeda I've seen in a long time. 

34 minutes ago, groberts said:

Intruiging - the host is Wordpress and I don't see the adds, honest! 

Unfortunately, am seeing 3 - 4 adverts. I'm seeing this on mobile if that helps? 

Great stuff Graham. 

By the way, you have some very weird ads going on in your website matey. Here's one example 🤣

32 minutes ago, Whirlwind said:

Yeah, that would help as there is some compression issues happening somewhere?

Try this now mate. 

https://we.tl/t-cuhXf0sM8t

24 minutes ago, Whirlwind said:

I've attached a comparison of the same stars between the image that shows that different in resolution.  The ringed one was giving a focal length of around 3500mm which seems high.  Also found out where the fixed noise was coming from. Apparently it was being added by the platesolve so that query is resolved.

If you want and helps, I can send you a higher res image?

10 minutes ago, Whirlwind said:

Are these the same two images or is the second one an uncompressed version of the first?  The plate solving of each one is completely different and there is obvious fixed pattern noise in the second compared to the first (which is much smoother and more random).  In the latter the ringing artefacts are much more apparent though.

For the love of God I can't remember. I think they're the same but the only difference is that the first image was right out from PI and the second one (marked with red) was something I did on my phone. If that made difference to the file then I don't know

1 hour ago, Whirlwind said:

I'm a bit confused but I don't see any ringing on these images?

I've marked the stars for you. You'll have to zoom in to see that. 

1 hour ago, Ken82 said:

Souls you had me thinking for a minute. I can see a small ring type artefact on the garnet star in my elephant image which is mag 4. Its very acceptable and only noticed under extreme zoom. So after finishing my pacman last night i pointed to alnitak and got a single HA + OII sub. No sign at all of it here. So apart from the microlensing id expect yours to be similar. 

 

Apologies for the delay in replying, just had a busy few days. 

Here are the single and stacked Ha subs. Look at the bottom right hand corner star which like I said is bigger of the bunch. 

Single:

Stacked:

No processing has been done apart from calibration frames applied.

4 hours ago, groberts said:

Doh!  Ah well, hope it works out, will be following your events. 

I'll be fitting mine soon + then need some clear skies , which on recent evidence seems unlikely.

Graham   

Cheers matey. I have emailed FLO with my findings who in turn have emailed Chroma who are inspecting the subs and stacked results. As soon as I hear back from them on this, I shall be updating. 

Yeah unfortunately the skies don't look promising for the upcoming weeks and I fear that if Chroma asks me to make a few more tests, it might be weeks if not a month at least before I can get back to them. 

1 hour ago, groberts said:

Souls: I wondered if you've seen this thread on CD on this issue, it's excellent and couldn't be clearer + seems to be a common problem:

https://www.cloudynights.com/topic/715162-chroma-3nm-orientation/

Meanwhile, I also heard back from Chroma who say: "In most cases orientation does not matter with these types of filters, but if you want the filter-coated side to face the sensor, if you read the writing on the edge of the filter, the filter coating will be right side up." 

This corresponds with the aforesaid CN thread. 

Good luck.

Graham

 

I

LOL mate, look back at the previous page and you asked me about this link and I gave it to you

That is exactly how I had mine fitted. 

My filters are definitely showing something just more than these concentric circles, it shows these weird halos around the stars at the edge of the field. All three filters. 

I've sent my images to Chroma and they are looking at it. Not sure if I can keep up with this if they come back to say that this is normal especially after what I've paid for them.

What an absolute cracking image. Well done Dave. 

1 hour ago, Whirlwind said:

That's fortunate and interesting because that would suggest a different manufacturing tolerance level.  For example it could be that the chip is tilted slightly or even that the cover slip isn't lying against the micro-lenses.  Still think the best option would be to run the numbers and see whether you get the same radius causing the effect in each filter as that would point to a specific piece of equipment.

You will have to probably dumb it down for me. Run what numbers and how? 

22 minutes ago, Adam J said:

My point was only that it may be a combination of factors so not the fault of the filters as such. It's up to you if you want to keep them of course.  

I totally get what you mean mate. Of course I spent top dollar to keep the filters and if they had worked with the gear combination that I have then I would have no leg to stand on. I'll be happy to have this set returned and to be replaced with another set. Not sure there's more I can do at this point. 

I found someone on Instagram who luckily has the absolute exact same setup as mine, even to the second scope. I've been exchanging messages with him and he was kind enough to share some single subs, stacked masters and processed image and they don't exhibit the same issue. 

Just wanted to put this out there. 

5 hours ago, Adam J said:

My sig is 2 years out of date so you can't work anything off my signature...

One thing I would say is that the place I have seen this effect more than any other is in narrow band images taken by the Hubble space telescope and I am sure there are no issues with its camera or filters. It will be a combination of  factors acting together as opposed to any single bit of kit being at fault. Hence I suspect op will just have to live with the effect. 

I'll ll be interested to hear what Chroma say none the less. 

Adam

 

Most certainly not just going to "live with the effect" if it doesn't work, they're going back and I'd be happy to buy the cheaper filters that don't have this effect/issue.