A Celestron FirstScope

I tend to end up with telescopes, they just appear on a semi-regular basis, given to me with the instructions to find a home for them. One of the latest additions to Andrew’s Home for Wayward Telescopes (AHWT) was a Celestron FirstScope. It was bequeathed to me by a co-worker moving to the mainland and thus dwelt for a time in my office, there being little room in my garage for yet another telescope.

Celestron FirstScope
A Celestron FirstScope in somewhat larger company
This telescope is now headed to a new home. With Christmas approaching another co-worker asked my opinion in buying a telescope for his eight year old daughter. She had expressed interest and he was wondering what to get. Quick to size an opportunity to divest myself of an unused telescope I let him know I had just the thing! One less mirror to clean. Rob of course was quick to seize on the idea of free.

The telescope is essentially brand new, once I dusted it off. The only problem was a lack of eyepieces for it. I hit up eBay for a set of cheap but acceptable Chinese eyepieces and that problem was solved. At least this one would not take weeks of work to return to service.

Before I handed it over I did spend a bit of time checking to see if everything was OK with this little telescope. I checked the collimation, giving the secondary a quick tweak. I then took it out into the driveway and looked at a couple stars and the Moon with it. The low power views were acceptable, this is probably what this scope is best at, low power sweeping of the sky. High power quickly revealed the limitation of the telescope.

The most serious drawback to this little telescope is the short focal length, only 300mm. At a fast f/4 the coma is significant. Using higher power eyepieces is fraught with issues and the image quality is not anything great. The little telescope was originally supplied with two eyepieces, a 20mm and a 4mm. I expect the performance with the 20mm was fine, not so much with the 4mm. While the kit I bought came with a 23mm, a 10mm and a 4mm, I just discarded the 4mm.

At only 13x with the 23mm eyepiece it is not much trouble to aim the telescope at a target. Even so, some sort of small finder would be a nice addition to the telescope. There are a couple screw mounts on the side to mount a finder and Celestron sells a small finder for the scope.

Newtonian Telescope
A replica of Sir Issac Newton’s second telescope
In using this small telescope I am reminded of Issac Newton’s first examples of a reflecting telescope, a design that now bears his name. This little telescope is a Newtonian, a direct descendant of those designs first made in 1672. The FirstScope is somewhat larger, at 75mm in place of the original 33mm, bit it is still a small, table-top instrument.

The telescope should fare well as a young girl’s first telescope. I will have to give dad a few lessons in using it to insure his reputation is safe. And there will also be an offer to look through a slightly larger instrument, an excuse to get the 18″ into the dark again. There are plenty of dark skies on this island to enjoy!

Author: Andrew

An electrical engineer, amateur astronomer, and diver, living and working on Mauna Kea, Hawai'i.

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