Image Quality- Small vs large aperture

Discussion of using SharpCap for Deep Sky Imaging
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Kopa
Posts: 21
Joined: Wed Jul 08, 2020 6:26 pm

Image Quality- Small vs large aperture

#1

Post by Kopa »

Dear all,

In terms of image quality, does aperture matter other than in capturing the image in a shorter time?

Am trying to stick to a budget but try and extract the best images for the price. I am looking at ASKAR FMA 180 £350 or StarTravel 102 OTA £210.

The FMA seems worth the money given it is an APO and already has a flattener/reducer in the price, but only a 40mm aperture.

The startravel 102 is an achromat and may need a field flattener/reducer but has 102mm aperture.

the ASKAR has Focus Ratio: f/5.5 (f4.5 with supplied reducer)
the102 has Focal Length: 500mm (f/4.9)

I will be using ZWO ASI 224MC camera.



Thanks
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admin
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Re: Image Quality- Small vs large aperture

#2

Post by admin »

Hi,

I have the Celestron version of the 102, and the colour correction (or lack of it) is a big problem for imaging with that telescope. I have no experience of the Askar though.

Anyway, really the choice is probably going to come down to the sort of imaging you plan on doing - presumably deep sky. Since the sensor you are planning to use is quite small, the shorter focal length of the Askar may be a big boost (you can get more of a galaxy or nebula into view). You can do some simulations of what you might see in the field of view in the two scopes here : https://astronomy.tools/calculators/field_of_view/

cheers,

Robin
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