C925, Mount, Allignment, Power Tanks, EP's & Collimation

[Mav359]

Hi everyone

thought i'd share.....

My power tank turned up yesterday, i really pleased with it, its a 300amp 8AH unit thats not at all heavy at all. It has two 12v outputs along with a 260psi air-comp, jumpstart, usb and its an invertor. After three hours use the charge has barely been touched.

As it has now turned up i was able to get my first real session (3.5hrs) tonight, i had previously had a go manually but tonight i could (because i had power) do the Two Star Allignment and i have to say i am sooooooo impressed by the ease at which i was able to polar align the scope, using the mount and then the allignment using the nexstar remote. Im sure that there was plenty of room for improvment and i want to get into astro-photography so it'll need to be better again but i (within 10mins) was able to have the scope point and track with very little adjustment & this was only the second time i have had the rig outside.

As for the rig i have only two very very small gripes, firstly... while i was having a play in the first un-powered session i was having a ridiculos time matching the finderscope to the OTA (in the end i gave up) but after some spot the difference between the instructions and the OTA i realised the finderscope bracket was mounted backwards. The only other niggle is that the remotes cable is way to short, im going to get an RJ11 extention cable tomorrow (dirt cheap) but you'd think they would have realised that.

Before purchasing the scope from FLO Steve recommended that i buy some thumbscrews from bobs knobs, which i did but after putting them in it became clear after my first session that the scope needed to be recollimated. Once agaiin Steve came to my rescue and told me a trick to collimate the scope, by placing it on a level surface at eyeline and slowly moving back you can see the concentric circles start to form and correct it from there. After tonights session my scope is perfectly collimated and i was able to do that in the day inside.

Lastly the EP's, i have a full set of Baader Hyperions and i have to say the quality & FOV is superb, they are also massively practical units, i was able to swap them out with ease with my gloves on.

Overall i am soooooooooooo pleased with the purchase after just one powered night i was looking at M42 and was blown away(massive grin on face) anyone thinking of buying the C925 on the CGEM mount will not be disappointed. Like wise the EP's are awsome i would deffo recommend them.

:D:D:D

Heres for some more clear skies

[ollypenrice]

Glad you are enjoying the scope. Could you say that trick from Steve more slowly? It sounds interesting but I don't get it. What are you looking at?

Olly

[Mav359]

You put the OTA on say a flat desk and look into the end of the scope and move back slowly with one eye closed you can see a group concentric circles surrounding the central obstruction.

If you move back a bit further you'll then see another set of concentric cirlces, these appeared to be formed by the reflection of the central obstruction.

So now you have two sets of cirlces to look at (remeber keep one eye closed) if you keep the second set concentric to the central obstruction then you will see that your central obstruction and second set of circles is or is not concentric with the first set of circles.

I then used my thumb screws to collimate the scope and last night when i defocused on some stars it appear bang on.

I'll see if i can photgraph it for a better explination but it deffo works.

[Mr Spock]

Yes, that's how you collimate SCTs and Maks. Just look down the tube from a distance equall to the focal length and the concentric circles become obvious, as does any miscollimation.

Simples!

[Mav359]

Its really hard to photograph so i have used my freaky cool photo shop skills to illustrate. You'll have to pretent the circles on my drawing are concentric

In the first picture when you look into the scope you see the first set of concentric circles, this is at about 2/3 feet away.

As you move backward away from the scope to about 5/6 feet the second set will appear.

Move your head until the second set is concentric with the central obstruction. you now collimate until these are both concentric with the first set.

It'll make more sense when you look ito your SCT