Go to Telescope

[Kasun]

Hi Everyone,

Trust all of you are enjoying the night sky 

I need some help. I currently own a Orion 10" dob and a 130sf Vixen  providing pretty good views. I'm in search of  a good go to scope that will give me good views of the  lunar , planets and the DSO's

After doing some research I have narrowed my options to the following but finding it very difficult to choose due to few specifications eg: the focal length / focal ration - Celestron NexStar 8SE GoTo Schmidt-Cassegrain Telescope /  Orion StarSeeker IV 150mm GoTo Mak-Cass Telescope / Orion StarSeeker IV 150mm GoTo Reflector Telescope 

Out o the above options currently the  Orion StarSeeker IV 150mm GoTo Reflector Telescope happens  to be the cost effective once with a decent mount but with a short focal length/ratio and the other two are far superior with reference to same and not to forget the 08" aperture on 8se.

Please be kind enough to provide some guidance in or do to make a decision.

Cheers,

Kasun 

[Putaendo Patrick]

Why not get just a go-to mount and use it with the Vixen as a start?

Later you could get a larger 6 or 8" reflector OTA (i.e just the tube!), perhaps second-hand?

Do you want go-to just for visual observing, or are you perhaps thinking of astrophotography somewhere down the line? This will in part dictate how good the go-to mount has to be!

Correction: I initially thought the Vixen was a refractor, but even so, I still wonder if the new mount is more important than a new telescope.

[Kasun]

Hello Proto Star. Thank you. Yes it makes sense and sounds like a plan after all Vixen is with pretty good optics. Can you recommend a good durable go to mount that can take up a 8" (max) probably  a cassegrain due to it's high focal length and f ratio ?? Cheers and clear skies every night

[Putaendo Patrick]

I'm afraid I don't know anything about astronomy suppliers in Sri Lanka (or if you plan to import directly), so I can't really help much on specific mounts.

However, in general, there are two types of go-to - Alt-az and Equatorial. The former are usually a simple arm which move the scope up-down and left-right. The latter swings the telescope to follow the apparent movement of the stars as our Earth rotates. Alt-az are cheaper but with limitations as to the weight they will support. They are not ideal for advanced astrophotography as the movement is a little jerky and the field doesn't rotate making long exposures difficult. Equatorials are usually more precise, and depending on the model, will support more weight - but are more complicated to set up as they need an accurate North/South orientation. And they are more expensive! Some go-tos offer both systems, but again, cost more.

There's a brief Orion video which may be useful at: http://uk.telescope.com/How-to-Choose-GoTo-Telescope-Mounts/p/115047.uts

180mm or 200mm Maksutov-Cassegrains OTAs weigh about 6 to 7.5 kg, plus any accessories. But, being small and compact, they will resist vibrations caused by any wind. Most basic Alt-az go-tos are specified to support a maximum of about 6kg, but check this out carefully for any models you are considering.

For purely visual observation, you could probably get away with the Skywatcher EQ3 PRO Synscan GOTO or something similar from another brand: https://www.firstlightoptics.com/skywatcher-mounts/skywatcher-eq3-pro-synscan-goto.html   But personally I would say this is right on the limit, and would try to go with the EQ5 or similar: https://www.firstlightoptics.com/skywatcher-mounts/skywatcher-eq5-pro-synscan-goto.html

[Kasun]

Thanks a mil Proto star. well I;m planning on getting down a go to from the US ansd Skywatcher is not very popular there as it's in Europe. tome to do some research again based on your advice. once again thank you. Cheers, Kasun

[Kasun]

Hellp Prptp star

Trust this finds you well.

The following set up was recommended to me by a person that I got to know - https://www.bhphotovideo.com/bnh/controller/home?O=&sku=917581&gclid=CI7rnank1s8CFQwTgQodYp0IWA&is=REG&ap=y&c3api=1876%2C92051678642%2C&A=details&Q=

For the little bit of experience that I have this looks pretty good to me. You being a well experienced person, please be kind enough to let me know your thoughts. 

Cheers,

Kasun 

[Putaendo Patrick]

Hi Kasun,

I'm afraid I'm not at all sure!

I always thought this model was a regular 8" reflector with a focal length of 1000mm BUT this looks physically smaller. According to the B&H description, it is effectively a 1000mm (39 inches) telescope in a shorter 27 inch long tube. This means there must be some optical device inside - and thus seems to be what is known as a Jones-Bird design.

Now look at the Celestron site: http://www.celestron.com/browse-shop/astronomy/telescopes/advanced-vx-8-newtonian-telescope

Here they claim the length of the telescope is 36 inches. Add the distance from the secondary mirror to the focuser and now you appear to have a real 1000mm focal length telescope.

So, are there two versions of this model? I am confused

If it is a Jones-Bird design (i.e. the tube is physically shorter than the focal length) I would very much avoid it, especially at this price.

However, reading a few reviews of the telescope I see no mention of this. The comments are generally that the focuser is not especially good quality and several people have opted to upgrade, for example, to Moonlite focusers.

The general opinion of Celestron's VX mount seems to be that it performs well. However, there do appear to have been quality control issues in the production and there seem to have been a few lemons out there! I guess these problems have now been corrected - but I would investigate this further. Getting this mount serviced in Sri Lanka would probably be very difficult, and I think you wouldn't be covered by any warranty outside the USA. Ideally you will be able to thoroughly test out your telescope in the US before bringing it home.

 

 

[Kasun]

Hello Proto Star. 

Hmmmmmm yeah i see . I need to contact celestron and get things verified. Just like you indicated my greatest worry is after spending so much money even on the eq mount if I receive  a lemon (I believe what it means is malfunctioning) I will have to go through complete trauma cos one thing I cannot get it serviced in Sri Lanka and to send it back for replacement would be a complete nightmare cos of the cost and hassle. Since I have the 10" dob and the Vixen. and since my primary requirement is to locate the objects, apart from the Skywatcher mount you recommended do you know anything good from Orion or Celestron that is not very expensive so once I receive the mount even if somethings wrong I can bear the loss  

Thank you for your time

Cheers

Kasun