Advice required

[Pat Dunne]

Hi All,

I have decided to take the plunge and dole out my filthy lucre and buy a Clestron CPC 925, my main interest is Lunar and Planetary observation with some deep sky as well.

I've a few questions to ask of the esteemed members of this forum:), what is do the the you think of the CPC925? Am I buying the right scope is there anything else out there I should looking at as well?

I need something that is reasonably portable (the 925 would appear to fit that bill) as I live in a city and need to travel to a good ob site.

Would also like you know, what equip you would recommend for viewing using a Laptop, I have a genny so power is not a problem.

Let me know what you think.

Cheers

[perrin6]

I believe a cooling system is important as they take a while to adjust to the outside temperature.

[brantuk]

Hi Pat - I really rate the cpc range highly. The optics are superb and the electronics work consistently and properly every time (so long as the powers right). I particularly like using binoviewers for "spacewalk feel" when observing.

For lunar and planetary it's hard to beat - very sharp and crisp. Maks have a slightly smaller secondary obstruction and longer focal length, but there's really not a lot in it between the two types.

For portability there are two very convenient and well centered carrying points that make the weight easy to bear - so popping it in the car is no problem. And the mount is extremely solid and stable.

I wouldn't like to put a 925 on a wedge though as it's a tad heavier than the 800. For alt/az mode the setup time is minimal. 45 mins cool down time is usually enough for my 800 and that gives it more than enough time get a gps lock on 3 satellites.

The tracking is excellent and will keep an object dead centre for 2-3 hrs before drift becomes noticeable. A power tank and dew shield I consider essential accessories.

Viewing via a laptop - look at Minitron and Watec cameras - I've only lightly looked into that but it seems the way to go. Finding stuff is totally controllable from computer.

Hope that helps

[brianb]

Not a lot to add except that a dew shield and a dew heater strap for the corrector plate are to all intents and purposes essential in the moist British climate.

Pack a reel of electrical tape so you can secure the top end of the power cable to the fork arm so that the connector doesn't pull out when the scope slews in azimuth.

[Phil Fargaze]

I am very interested with Pats questions regarding the Celestron 925. I am getting a gentle tug in the direction of obtaining one as well (OTA that is). May I add another question regarding the field of view. Would the fov be limited for deep sky observing or would it be fine with suitable eyepieces being used?

[barkis]

The scope is a good un. I have friend who owns one, and more than happy with it.

You say you have a Generator. I would really hope it is a stable and smooth output. The electronics in the mount won't take kindly to surges and spikes. Get a portable 12 volt DC Power Tank, and use the Genny to power the Tanks Battery charger when it needs replenished.

Ron.

[brantuk]

Phil - remind me at Kelling and we can try out my "as yet unused" reducer to check the fov on dso viewing

[brianb]

Would the fov be limited for deep sky observing or would it be fine with suitable eyepieces being used?

Yes it's limited ... the focal length is 2350 mm so even with a long 2" wide field eyepiece the actual FoV is not enough to fit in the Pleiades ... the moon is a pretty tight fit.

Fact of the matter is, a small short focus ED refractor is a better scope for getting a big field of view.

OTOH the CPC 800/925/1100 will give excellent views of smaller, fainter DSOs that a richfield refractor can't show. And it has sufficient aperture to give really detailed views of the planets (when the seeing is reasonably steady) ... the CPC range (and the Meade LX90 range which are similar in design) is just about the most transportable means of getting that much aperture.

[Nexus 6]

Hi Pat, I have to slightly disagree with Brantuk with one point, for me its just a bit too much for taking out so I stick to home with it, I would strongly recommend you aqcuire a means to protect the ota/fork assembly, its not something I would dare move without adequate protection.

Should you wish to cool it down quickly you can take everything out at the visual back end and turn it with the tube facing upwards, that will allow thermal currents to escape quicker. I normally leave mine for around an hour to allow it to cool without doing this as I don't want to risk dropping anything but it does work.

As for impressions on the ability of the scope, well there's nothing else to say, I only use mine for visual so can't comment on asto imaging using one but apart from the weight, 58lbs (26.3 kilos), thats it. I have really enjoyed the views it has presented and you do have the bonus that you can release the clutches and use it without any power, a great way in honing your knowledge of the night sky

Good luck with it.

[Merlin66]

I use the C925 on a NEQ6pro mount - majic!

A very capable instrument.

[michael.h.f.wilkinson]

Yes it's limited ... the focal length is 2350 mm so even with a long 2" wide field eyepiece the actual FoV is not enough to fit in the Pleiades ... the moon is a pretty tight fit.

Fact of the matter is, a small short focus ED refractor is a better scope for getting a big field of view.

The first point is not quite right. In my C8 I can fit the Pleiades in the FOV of the 40mm Paragon. In the C9.25 this would not quite fit, but the moon fits easily in the FOV (1.16 deg for the Paragon in the C9.25, vs 1.38 deg for my C8). The moon is a tight fit in the FOV of my 14mm UWA (at 140x )

I agree with the last point you make (which is why I got the APM 80mm).

[brantuk]

"I have to slightly disagree with Brantuk with one point, for me its just a bit too much for taking out"

Nexus is right here - I did have my 800 in mind, but the 925 is heavier so if you ain't fit it might be a struggle. I wouldn't want to lift a 925 onto a wedge either - the 800 is the limit for me

[Merlin66]

Believe me the C9.25 OTA is only 10.4Kg compared to 14.7Kg for the 10" Lx200 OTA - it feels "empty" by comparison.... for me with a history of back surgery it's a walk in the park!

(Brantuk and others - whooops I see we're actually talking about the CPC version c/w mount....sorry!)

[Dave Smith]

I once borrowed a wedge to try my 9.25 on it. It wasn't as bad as I thought it was going to be to put it on the wedge and I'm a 70 year old only moderately fit person. I decided against a wedge, not because of the weight but for other reasons and have since mounted mine on an NEQ6. Out of the forks it is MUCH lighter.

To get a wider field of view a focal reducer makes it f6.3. I can see the whole of the Pleiades with my Moonfish 30mm 80 degree eyepiece.

Dave

[brantuk]

Oh heck!! I must be a whimp lol

[Dave Smith]

Oh heck!! I must be a whimp lol

Not at all. When you lug the 9.25 out in it's forks to put on the tripod, the thought of lifting it higher and putting the bolts in at the same time seems impossible. But you already have one bolt partly in and that goes into a slot at the top of the wedge and you are then immediately relieved of the weight and can fit the other bolts at leisure.

It is much easier than you would imagine.

Dave

[brantuk]

Yup Dave - that's how I get the 800 up on the wedge. But I have to get someone to do the first bolt up once in the slot. I think it has more to do with smoking and lack of exercise in my case lol

[brianb]

It is much easier than you would imagine.

Maybe, but the thought of doing this with my CPC1100 OTA fills me with terror. If I wanted to equatorially mount a C11 OTA I'd stuff it on a good German equatorial & not have to lift the mount at the same time as the OTA ... I guess a C11 OTA would sit very happily on an EQ6 & still be a (sort of) portable setup.

The CPC 925 actually isn't much lighter than the CPC 1100 (only a few pounds lighter). I believe the CPC 800 has a "lightened" mount with no bearing in one fork, which makes it significantly less rigid though quite adequate to deal with the shorter & lighter 8" OTA.

[Pat Dunne]

Guys, many thanks for all the replies.

The weight aspect wont be a problem as I am fairly use to lifting and dragging.

Glad to hear the the optics are what I was expecting.

I will reserch a little more for a hook up for viewing through my PC.

Will certainly take on board the advice regarding the possibility of power surges.

Cheers for all the assistance. Will let you all know how I fair out when I get the new toy.