ASI 2600 MC Pro - Spikes on bright stars

Gernot

Hello fellow astro enthusiasts!

I have a problem with my ASI 2600 MC Pro... When used with an ASKAR SQA55, the setup produces spikes on very bright stars. I've already discussed this with colleagues, and they have beautiful stars with the same combination (2600MC Pro + SQA55).

I checked the image train and cleaned the front window of the camera so that these two factors can be ruled out as the cause of the problem.

Vega

Surprisingly, when I use the SQA55 with my Canon RA, the star image is fine.

Vega

Do you have any idea what could be going on?

CS Gernot

Kevin_A

That SQA55 scope has aperture blades so it will produce some spikes on stars. Some users are reporting spikes while others not as much. The reason it does not show up on your Canon Ra camera is that the Ra sensor has an anti alias (AA) filter on it which blurs and softens the image slightly. All camera sensors using AA FILTERS will reduce star spikes at the expense of a slight blurring of the image. The 2600 does not have a AA filter. If the sensor glass or sensor is clean then that is 100% the reason. Also make sure the scope is set wide open at f4.8 as it will be far worse at higher f ratios just like a camera lens. A tighter assembled optic will also increase spikes so try a dew heater to reduce this as it helps with slightly pinched tight optics when it may be colder outside.

Gernot

Kevin_A

Hello Kevin!

Thanks for your detailed answer. I wasn't aware of the filter properties of the Canon Ra, and that makes sense.

A colleague used a similar setup (2600 MC Air + SQA55) and his results showed no spikes!

https://forum.astronomie.de/threads/challenge-sqa-55-vs-tsa-120.381895/post-2021437

I'll contact the dealer and see what they say...

Thanks again, and CS

Gernot