Need Advise to buy a telescope

[Arshad Wali Muhammad]

Hi. I want to buy Celestron Evolution 9.25 with startsense. I have heard star sense isn’t avbl in 9.25 but 8.0. Is it true ? Is starsense very useful ? What’s actually is starsense is ? Because I’m not interested in 8 inch. Secondly is it better then 11 inch  CGX EQUATORIAL 1100 SCHMIDT-CASSEGRAIN TELESCOPE? If not what’s the difference in terms of object clearity ? Secondly is Celestron motorized ? I mean to say the object moves very fast, so can it track the object live ? Please advise. 

[Cosmic Geoff]

I think you should download the specification and product description sheets and read them.

You can buy any of the Celestron scopes without the Starsense if you shop around. The Starsense is an accessory which some dealers are bundling with the high priced scopes. Or you can order the Starsense separately at any time and attach it yourself.

Briefly, the Starsense automates the alignment part of the setup procedure. It eliminates a tiresome operation and saves some time. Whether this is worth £300 in your currency is up to you.

Edited May 17, 2020 by Cosmic Geoff

[Dr Strange]

The 9.25 is a very good visual scope. It isn't so good for astro photography. It is also a heavy scope. It is 9 kg for the tube alone. My advice would be to move to the 11" since it is only 12.7 kg which isn't much more than the 9.25 and gives you significantly more light grasp. Having said that I would recommend the 203mm/8" EdgeHD version. Reason being is that with the EdgeHD you get refractor (uses lens) like views from a reflector (uses mirrors), it has the option of installing the TEMPest fans from Deep Space Products which take the time to cool the mirrors down by about 1/2 so you go from waiting an hour+ for the mirrors to cool to about 30 minutes, and it is designed to use as a astro photography (AP) scope for both deep space objects (DSO) and planets though you will want an equatorial mount for AP.

As to the StarSense, it is a way to completely automate the alignment process of the mount. With a GOTO mount you have to align it so it knows where it is in the world. You do this by centering 2 stars in the eyepiece (EP) for alignment then 2-4 additional stars to calibrate the alignment. The more calibration stars you use the better the alignment and the better it will point to objects. With my Celestron mounts I always use 4 calibration stars. This can be a time saver and make the process more automatic. You need to decide if this is something worth the extra money or not. 

[Arshad Wali Muhammad]

Thank You very much I have bought Celestron CPC 1100 EdgeHD, but what’s TemPest fans ? and where to fit? Secondly they sent Alt Azm Mount so can I add wedge ? I live near equator. 

[Cosmic Geoff]

The TEMPest fans are presumably designed to circulate air through the tube so that the optics cool down to ambient temperature more quickly and achieve best performance  sooner.  Before buying them, you should carefully check the specification of the EDGE HD 1100 to see if it doesn't already include equivalent fans.

Re the wedge, first explain why you want to put the scope on a wedge. This will convert the mount to a fork equatorial mount, which would only be required for long exposure imaging of deep space objects.  Despite what the manufacturers and retailers may say, feedback from users of these scopes is that after trying the wedge for these purposes many of them give up and buy a German equatorial mount and a different telescope for the purpose.   If this is indeed your aim, I suggest the additional purchase of an EQ-6 Sky-watcher mount and a small aperture short focal length apochromatic telescope, and the book "Making Every Photon Count."  

[Cosmic Geoff]

Also, if you live near the equator, I think I am correct in saying that putting the CPC1100 on a wedge would entail laying the mount almost on its side, which could place an excessive strain on the bearings.

[Stu]

8 hours ago, Arshad Wali Muhammad said:

Thank You very much I have bought Celestron CPC 1100 EdgeHD, but what’s TemPest fans ? and where to fit? Secondly they sent Alt Azm Mount so can I add wedge ? I live near equator. 

These are the ones, should be able to get some specifically for your scope. The Edge optics actually block the rear baffle tube I believe, making cooling harder so these fans seem like a good idea.

https://www.deepspaceproducts.com/product/temp-est-temperature-equilibration-system-for-telescopes---for-edge-hd-and-vented-standard-celestron-scts

[Arshad Wali Muhammad]

Thank You all.