Celestron C100-ED, initial impressions and thoughts :)

[Totnesdave]

Well, I assembled the Celestron C100-ED refractor yesterday, my first telescope in 25 years so lots to learn and a few issues encountered

Here's my first thoughts......

The Optics

First Light, astronomically speaking, is yet to happen ('new scope' weather:D) although I did check it out and roughly collimate the finder against a high treetop just over half a mile distant, nice crisp views of the top twig and a solitary leaf !

The Clamshell

I really had concerns over this after reading snippets on the web, and have also got a couple of standard rings inbound in the post. On the whole though I'm pleasantly surprised. It *can* be tight but the hasps do locate in a choice of three small grooves, which gives some coarse control over locking pressure. Operating the clamshell is pretty easy particularly if not over tightened. Its dovetail fitting into the mount seems secure with the two screws, but I would feel happier with some mounting relief as on the standard shorty dovetail bar supplied.

The Focusser

Lubricant a bit sticky if you brush against the rack, but it operates well enough by the standards of what I am used to. Any upgrade is ... for me ... very much a future concern

The Lens cap

Oh dear, bit of a badly secured disaster area is this, and due to the fancy shape of the dew cover, not sure a standard cap will fit, at 120mm internal and 126mm external dimension. However I have ordered one of these : Lenscoat hoodie Lens Cap XL to go over the top, which hopefully will keep the cap more firmly in place and more reliably covered and secure for transit.

Motorising.

I chose to retrofit RA/Dec drives to the CG-5 mount using this : DK-3 drive unit. No 'orrible fragile telephone sockets here, it features nice robust DIN plugs and sockets, quality brass gears and nicely machined housings, works beautifully, quietly and offers a 32x 'fast' slew rate. Fitting was mostly easy though I needed to add a 2mm shim (cut from a bit of hardback notebook cover) between the RA motor and the mount to achieve the correct pinion depth. I worked on antique clocks for a while so am fussy!. I am very pleased with the overall result.

I am puzzled by polar scope fitting...I see the location where this goes into the CG-5 mount, but removing the cap from the corresponding end, I can't see how such a device has a clear view through the mount as there is internal structure in the way, perhaps someone can enlighten me here ? Also, what appears to be a bell shaped cover for the polar scope area does not really attach firmly enough to leave in place.

Overall though, i think it is a beautiful instrument at a cost effective price (£395) which I'm looking forward to getting out under the night sky with

I've ditched the idea of a 'starter eyepiece set', after much reading round decided its more fun and long-term-useful to purchase specific to my preferences, which I've spent many hours pinning down, at least for the moment

Picked up a few cheapies such as TAL 7.5 and 40mm at about a tenner each from astroboot and a Meade 6mm, which has served to make me realise I do not like peering through tiny holes

The 20mm plossl supplied is actually quite nice, and I'm currently getting hold of the following, which I feel will cover my main needs :

- Meade 5000 SWA 24mm for deep sky/starfields , they are available at amazing discount from the USA right now (about 60 quid)

- Burgess/TMB 6mm Planetary, again, available for about 50 quid currently, and planetary observing is a fave of mine.

- Baader Hyperion 8-24 Zoom, for the donkey work of conveniently browsing my way round the sky, I think it's a good investment, from what I hear. Not sure of the ETA on these but I can wait

- Celestron Ultima Barlow : to add additional flexibility to all the above.

Mmmm, been selling excess musical equipment to help finance the extra goodies .. too many expensive hobbies

cheers

Dave

[jgs001]

That looks very good Dave... if it's anything like the 80ED it'll be a fine instrument. One thing you can do to help out the focuser, remove slop from the drawtube anyway, is to fit strips of teflon tape along the sides. It's a lot cheaper than replacing the focuser and makes quite a difference.

[John]

Nice report Dave - I'll bet you are really looking forward to first light

On the CG5 polar scope things (applies to all EQ5's as well):

- the declination axis of the mount needs to be at just the right position to ensure that the shaft through the RA axis in which the polar scope sits is unobstructed - I'm not saying it's a great design but that's just how it is with other mounts of this type as well.

- the polar scope dust cover (the bell shaped cover) is one of the 1st things to get lost / broken with these mounts so I'd take it off and keep it safely somewhere.

Hope you get it under the stars soon - they are great scopes - I had one of the original blue tube Skywatcher ED100's (same optics as yours) and really wish I'd not sold it .....

[david o]

Dave, the loosely fitting lens cap and polar 'scope dust cover can be cured.

Use strips of flocking paper (or any sticky-backed, "velvet" faced paper) on the "contact" surfaces of the caps to take out the slop.

Simples.

[Totnesdave]

Mmmm, I never thought of that, good old tape

Anyhow, been in the back garden under the sky for 3 hours before the full moon stuck its head up and washed me out. Rather a bright sky and not great darkness from the back garden, but ideal for getting used to the beast. Lovely views of Saturn/Titan, Mars, various nice easy doubles. It was so easy to get straight to objects with macro, micro and motor slewing plus the decently good finder, and the drives were a joy to use Loving the CG-5, really nice mount. Bit short on EPs, but managed with the supplied 20mm and my new Ultima Barlow mainly, plus the TAL 7.5mm. Looking forward to a proper dark sky

As Tony the tiger would say: "It's grrrreat !"