Which scope?

[Richard N]

I have two scopes that I could use with my Baader ASTF. Svbony 80ed SV503 and a Meade ETX90. Which would be the best choice and why? Visual only. 

[mikeDnight]

If the eyepieces that SvBony make are anything to go by, the 80mm should be very nice. It will offer a wide field field view and with a barlow will deliver nice views of the Moon, Sun and Planets. With a binoviewer it will give truly excellent views of the solar system.  The 90mm has a longer focal length and won't give a wide field option, but it will be very nice optically, especially on solar system targets and double stars. I recon that both are potentially very good telescopes in their aperture class!

[RT65CB-SWL]

I personally would use any refractor than a catadioptric for solar observation/viewing. Catadioptric ‘scopes tend to be ’sealed’ tubes and may well hold the heat longer. There have been instances where the adhesive/glue that holds the secondary baffle in place on some ETX’s has melted and fallen off.

Edited March 10 by RT65CB-SWL

[Elp]

If that's an 80mm Vs 90mm aperture comparison there's not much in it, as per the above the refractor may be the better option, it'll also be slightly sharper.

[Richard N]

Thanks all. The 80/90 mm was not really the main factor I was considering. It was more to do with the focal length. The point about the glue in the ETX is a good one! I might take a risk and give it a go though. The Baader filter acts as a sunshade. 

[Stu]

28 minutes ago, Richard N said:

Thanks all. The 80/90 mm was not really the main factor I was considering. It was more to do with the focal length. The point about the glue in the ETX is a good one! I might take a risk and give it a go though. The Baader filter acts as a sunshade. 

With Baader AstroSolar film as a full aperture filter, you don’t need to worry at all about anything melting inside. If it was doing that, your eyeball would be melting too!

I would likely go with the refractor as the apertures are very close and the unobstructed scope will likely do a little better. Could be wrong to, so try both! 

[RT65CB-SWL]

19 hours ago, Stu said:

When I observed the 1999 solar eclipse from BG🇧🇬 one of our group bought along his ETX-90 and homemade Baader solar filter. He said he preferred the view from my TeleVue Ranger. Whether having a Thousand Oaks glass solar filter made the difference, I don’t know.

Always get into the habit of checking full aperture filters before each and every use. If in doubt, do not use and discard it. My full aperture filter has a few microscopic pin-holes when I hold it up to a source of bright light and I don’t use it. I now use a Herschel wedge when I observe the Sun. [images below].

note: Herschel wedges can only be used with refractor ‘scopes. Do not use with any reflecting or Petzval designs/types of telescope or camera lens.

Edited March 11 by RT65CB-SWL