Scope arrives and clouds roll in

[issdaol (Phil)]

Originally Posted by Somnium

i would have thought that the primary would be the thing to shift given it's mass, but maybe that is because i am used to Newts, perhaps these scopes are designed to hold collimation in the primary.

looking through the TAK scope everything looks perfect, just there is a slight difference in thickness in the outer white circle (the light annulus). my understanding is that this is caused by a primary mirror collimation issue but are you suggesting that if i adjust the secondary this might resolve the issue?

Hmmm now that is interesting.

The mirror mounting on the Mewlon 300 is designed to align the primary in the factory and minimise movements of the primary ... so it is very rare for the primary to move or need adjustment.

While I am no Newt/Dob expert this is very different to the mounting of the primary in Newts which in my experience talking to Newt owners is much more susceptible to the primary moving and needing alignment.

ODK/CDK/IDK are not cheap scopes so I would be very surprised if their Primary Mirror Cell is not as good as a Mewlon 300's

The Tak collimation scope need to be moved in wards and outwards to change focus on the elements you are aligning.

If you focus the Tak scope on the secondary baffle you should see 2 large circles with a thin white circle in between .... all with equal distance on all sides.

If not and one side looks like a darker circle ...... then the secondary baffle or spider needs adjustment.

It's hard to guess without looking myself to see so hope what I am describing makes sense

Cheers Phil

[Somnium (Aidan)]

Originally Posted by issdaol

Hmmm now that is interesting.

The mirror mounting on the Mewlon 300 is designed to align the primary in the factory and minimise movements of the primary ... so it is very rare for the primary to move or need adjustment.

While I am no Newt/Dob expert this is very different to the mounting of the primary in Newts which in my experience talking to Newt owners is much more susceptible to the primary moving and needing alignment.

ODK/CDK/IDK are not cheap scopes so I would be very surprised if their Primary Mirror Cell is not as good as a Mewlon 300's

The Tak collimation scope need to be moved in wards and outwards to change focus on the elements you are aligning.

If you focus the Tak scope on the secondary baffle you should see 2 large circles with a thin white circle in between .... all with equal distance on all sides.

If not and one side looks like a darker circle ...... then the secondary baffle or spider needs adjustment.

It's hard to guess without looking myself to see so hope what I am describing makes sense

Cheers Phil

Thanks Phill, i dont particularly want to be playing around with the spider and the baffles just yet, i think the solution is much simpler than that, it is either the primary or secondary that is just slightly out. i will have a play around with the laser to see if i cant get some consistent results for the secondary and use a TAK scope for the primary, unless anyone can tell me how to collimate the secondary without a laser and without a central dot

[gregbradley]

Beautiful setup. Which Microline did you get?

It appears to be a well made scope.

The CDK comes with collimation instructions and an eyepiece and adapter to set the distance for the primary and secondary although you would expect that to be correct from the factory.

With that much weight on a PMX make sure its well balanced.

If you can you are better off having the counter weights higher up the shaft and no counterweight shaft extension. A possible source of flex.

Greg.

[Somnium (Aidan)]

Originally Posted by gregbradley

Beautiful setup. Which Microline did you get?

It appears to be a well made scope.

The CDK comes with collimation instructions and an eyepiece and adapter to set the distance for the primary and secondary although you would expect that to be correct from the factory.

With that much weight on a PMX make sure its well balanced.

If you can you are better off having the counter weights higher up the shaft and no counterweight shaft extension. A possible source of flex.

Greg.

Thanks Greg, doesn't really compare to yours but i am happy with it

i have a microline 8300 with a CFW 2-7. i know it is not perfectly matched to the scope, i will probably end up doing a lot of 2x2 binning. eventually i want to replace that with the 16200 but right now the wallet is a little light.

the primary secondary distance is set with collimation only taking place on 2 of the 3 collimation screws, the scope came with collimation instructions and says to use a laser to align the secondary and then do a defocused star test to check that it is perfect, then adjust the primary by analysing the edges of an image. i think i will get the secondary as close as possible using my glatter then use my Tak to check on the primary and refine based on star tests.

the scope is actually really well balanced at the moment, i am trying to keep the weight distribution simple so i am not adding any piggy backing or off axis weight. i was weighing up the option to use the extension or buy another counterweight. if i have issues with flex i will get another CW down the track. The weight doesn't appear to be overwhelming the mount at all, the scope is actually relatively light, about 25 kgs for the OTA and my imaging train is relatively light too. but i guess all the issues will come out when i try to get some long exposures

[gregbradley]

Sounds great.Looking forward to first light. Feel free to ask any questions. I used a FLI ML 8300 for several years.

Greg.

[Somnium (Aidan)]

Originally Posted by gregbradley

Sounds great.Looking forward to first light. Feel free to ask any questions. I used a FLI ML 8300 for several years.

Greg.

believe me i will i am chomping at the bit to get down there on Saturday, hopefully i can post first light.