Nubian

On 24/05/2019 at 23:26, symmetal said:

It's just that png files, like jpg, display directly on the forum so don't need to be downloaded to view them. 

As Dave said, slight coma, predominantly bottom right. Better than the other RedCat images shown here. Interestingly CCD Inspector gave it a 'good' result with all four corners similar and the centre slightly out of focus. Probably not enough stars for a proper assessment as it only found 523 stars. Around 3000 or more stars are needed fairly evenly spread over the image give the best results.

Alan

Hi Alan,

i took some more test exposures tonight. EOS 700D, 20s, ISO 800

Still got some issues with the star adventurer, but I hope this one has enough stars for a proper analysis.

What do you think?

13 minutes ago, Davey-T said:

Could you post as PNG to save downloading Tif

Thanks

Dave

Not sure if Im getting your point. You mean because of the size? ok, I attached a compressed png

or download: https://drive.google.com/open?id=1FAvYLYhUXjLzzV1tuoqf6HaWBfcL8YgB

On 17/05/2019 at 15:25, symmetal said:

As Dave said a single image is all you need. As the coma, if present, is usually more evident on the edges of the image, a larger sensor (as on a DSLR) will show problems which may not be apparent on a small sensor.

If there is coma you can see it yourself visually when examining the image (especially in the corners) where the stars have fan shaped smears from the star centre. If you can't see any you're lucky and have a good lens.

A fits file is the normal file format from astro cameras and the fits file header includes useful information about the image but isn't necessary. From a DSLR just convert its output file to a tif or png file, which CCD Inspector can read. I'm not sure if it can read DSLR raw files. The CCD Inspector just gives a more accurate display of the star shapes/sizes though will interpret coma as a curvature/tilt problem though that is not always the correct interpretation. The coloured CCDI plot is very useful as a quick check that the image is good or has problems.

Alan

Thx for your replies mates!

Since Im waiting for my star adventurer being returned from RMA, my father had to take test exposures. Sky wasn´t 100% clear, but maybe the shots are good enough for evaluation?

60s exp with a Canon 80D:

https://drive.google.com/file/d/1Vg9ud-6eTGZdRFO2LVh95TZfXPEl3JfK/view

Would appreciate if you could tell me, if the RC needs to be recalibrated.

Henning

My RC also arrived this week! 😀

Do I need to take several images for the coma test? How do I evaluate the results correctly?

Someone here uploaded a fits file. What is it important for?

Well, his replacement has shown the same coma.

But you are right. I'll relax now and look forward to my first telescope ever! Im a real noob on astrophotography and I'm so excited to hold this thing in my hands soon

It took me quite a while to get into this hobby. This picture shows myself in 1983 or so with my hands on my fathers balcony mounted refractor

I purchased from FLO but Im still waiting for delivery. I was just curious how possible issues will be handled

If "our" Redcats show the same coma, shall we send it to Es or will FLO take care of the adjustment? If not, how much does Ed take?

Compared to other scopes, how bad are the results? Would i notice the problem on a crop camera?

The sharpest 250, but not the flattest?

When I look at this one here:

https://www.astrobin.com/full/391674/0/?real=&mod=

the stars on the right are everything but round. ;(

Thanks for testing Alan! Im still waiting for the RC with my name on it.

I can't deny that I'm a little concerned now. After all this hype about the "sharpest 250mm" nobody wants to read about results like yours.

I hope there will be more customer reviews soon and maybe we get feedback from Es Reid too.

Henning