CPC800 GPS setup and dew questions

[Gilps]

Merry Christmas everyone

Well the day finally arrived yesterday when we managed to get my wife's new Xmas present unwrapped - a used CPC800.

As part of the prep I upgraded the hand controller firmaware a couple of weeks ago, but yesterday was the first chance to try the scope out. When I switch the scope on I get the GPS linking message, and it does seem to pick up a time. When I went in to the menu to check the scope settings it seems to have got the long/lat sorted out but the time was several hours behind. The time zone was set to Pacific West (or something similar) and daylight saving is set. Do I still need to change settings or should the GPS handle it all for me? If I need to make changes where do I do it as the manuall seems unclear? It says just switch on and go, but something is not quite right.

As we couldn't get the GPS set right, we figured we would just have a play manually. We found Jupiter and were enjoying it so clearly, both through the finder scope and the OTA with a 10mm Hyperion, when the dreaded dew hit. I say dew, it was actually frost. I had allowed the scope to cool for a couple of hours, but hadn't switched on the dew strap as I figured it would slow down the process. So my questions are regarding the use of the Kendrick dew system.

When I did get around to turning the system on - I have a Kendrick Digifire 7 controller and a strap for the 8" tube - the lights came on OK. I checked the power setting, it was at 60%. After a few minutes nothing had changed, so I upped the power to 100%. It was now down to -8C by this stage! Still no change with the dew/frost so we called it a night.

Am I just expecting too much of the dew strap to be able to handle those kind of temperatures?

Should I switch the dew controller on earlier, like when I first put the scope outside, or let it cool down first then put it on?

Should the dew strap feel warm to the touch when switched on, as mine didn't? Maybe that was just due to the cold.

Despite our small problems, and the short viewing time we had last night, we are very impressed with the scope and are looking forwards to many warmer evenings.

[Martin Whitaker]

Hi Gilps, I have a cpc800 but have only used it about 4 times.

I have not as yet used my new dew strip or controller so cannot comment on that other than to say that in the dew controller info it states that you should start with the highest setting and back it off down to the setting which keeps the dew off.

Also to turn it on as soon as you set up.

My first nite with the cpc was not as expected as I did not realise you should set the time /date and dylight saving part, also the tripod settled out of level on the lawn during use.

Second time out I worked perfect as I had lots of help from fellow members- such as brantuc.

Hope this small info helps.

Cheers.

Martin

[brantuk]

Hi Gilps - the only thing I needed to set was the time zone and daylight saving - then the GPS does the rest. One common trap though (which I also fell into) was the tracking mode. Make sure it knows you are in the northern hemisphere and set in alt/az mode. If you are using a wedge you'll want EQNorth setting.

Which manual do you have? The correct one is very detailed and you can find it here: CPC 800 GPS (XLT) Computerized Telescope (item #11073-XLT) / CPC Series Computerized Telescopes / Telescopes / Products / Celestron.com There's a link to it at the bottom of that page.

As for dew - first line of defence is a dew shield - I use the Celestron one but Astrozap do a nice 8" one or you can make one from velcro and a camping matress.

I use my dew strap on the corrector plate - get it as close as possible but it's a tad fiddly under the dew shield. Some folk use a second one round the primary mirror section too. Keep ep's in your pocket to keep them clear - or use an ep dewstrap if it stays on for any length of time.

Sometimes heavy dew can overcome even the best straps - a hair drier on low swished round the inside of the dew shield can help keep it at bay. Don't blow directly on the corrector plate in these temperatures or you may risk cracking it.

Hope that helps.

Cheers

[BlueAstra]

I have the 8se which I think is the same OTA as the cpc800. I have an astrozap dew shield and a separate astrozap 8" dew strap and dual channel controller from here: Dew Prevention . For the last few nights its been outside for six hours or more at -5 to -10C and I've never had a dew problem (although my targets have not been vertically upward!). You wouldn't believe the frost layer on top of the scope and shield.

[Gilps]

Hi Gilps - the only thing I needed to set was the time zone and daylight saving - then the GPS does the rest. One common trap though (which I also fell into) was the tracking mode. Make sure it knows you are in the northern hemisphere and set in alt/az mode. If you are using a wedge you'll want EQNorth setting.

I presume that to set the time zone and daylight saving, I have to press Undo when doing the Alignment process at startup, as I can't find where else to change it. I'm guessing that I need the Universal time setting, and to turn DS off (standard time).

Which manual do you have? The correct one is very detailed and you can find it here: CPC 800 GPS (XLT) Computerized Telescope (item #11073-XLT) / CPC Series Computerized Telescopes / Telescopes / Products / Celestron.com There's a link to it at the bottom of that page.

That's a big help thanks. My manual has a copyright notice on the back page dated 2006, your link is to a 2009 version. I guess that means my scope may even be 4 years old then, although I suppose Celestron may have used the 2006 manual for more than just that year. I wasn't sure how old the scope was when I bought it. The seller didn't have the original receipt, so this may help me date it. It's a bit irrelevant I suppose as it works fine.

As for dew - first line of defence is a dew shield - I use the Celestron one but Astrozap do a nice 8" one or you can make one from velcro and a camping matress.

I use my dew strap on the corrector plate - get it as close as possible but it's a tad fiddly under the dew shield. Some folk use a second one round the primary mirror section too. Keep ep's in your pocket to keep them clear - or use an ep dewstrap if it stays on for any length of time.

Sometimes heavy dew can overcome even the best straps - a hair drier on low swished round the inside of the dew shield can help keep it at bay. Don't blow directly on the corrector plate in these temperatures or you may risk cracking it.

Hope that helps.

Cheers

I've got an Astrozap shield but in our rush to get going we didn't bother to fit it as we thought the strap would be enough.

Hopefully tonight will be another clear one and we'll get to try again.

Thanks everyone for the advice.

[brantuk]

There's a complete breakdown of the menu system on page 26. As you've updated the handset you should see all the options currently available. If there's any missing then that may help you to date it.

[Gilps]

We finally manged to get a partially clear sky last night so set the scope up again. We did the SkyAlign and the first time it seemed to work OK. The message came up saying the alignment had worked. However, when we told it to goto Juptier, or several other objects it clearly went to the wrong place.

Then we went throught the alignemnt again, using the same stars as the first time, and this time it worked perfectly. The clouds kept coming in and out, but when they were clear we got some great views and the goto worked well.

We've crakced the dew problem now and the dew heater and dew shield worked real well. Even though the clouds became too much of a problem for decent viewing, we left the scope up and running for 3.5 hours to test the dew heater and there was no dew at all.

We are so excited now that we've had a taste of what it can do. All we need now is a clear night.

[m.tweedy]

We finally manged to get a partially clear sky last night so set the scope up again. We did the SkyAlign and the first time it seemed to work OK. The message came up saying the alignment had worked. However, when we told it to goto Juptier, or several other objects it clearly went to the wrong place.

Then we went throught the alignemnt again, using the same stars as the first time, and this time it worked perfectly. The clouds kept coming in and out, but when they were clear we got some great views and the goto worked well.

We've crakced the dew problem now and the dew heater and dew shield worked real well. Even though the clouds became too much of a problem for decent viewing, we left the scope up and running for 3.5 hours to test the dew heater and there was no dew at all.

We are so excited now that we've had a taste of what it can do. All we need now is a clear night.

Really pleasing to hear. the next part of your journey of discovery is to attend a star party and/or join your local astro society..

to help you plan your evenings entertainment you can use either this

Welcome to FaintFuzzies.com

or print out an observing plan with your co-ordinates

Tonight's Sky Main Page

[Zakalwe]

I used my 8" Nexstar GPS on a couple of nights when the temps. dropped to -8. I had no dew straps on the 'scope, just the Celestron dew shield. The 'scope body was thick with ice, but the dewshield kept the corrector clear. I was imaging M42, so it wasn't pointed at the zenith.

Don't underestimate a simple dewshield:icon_salut: