Mak disappointment

[banjaxed]

I finally got to use my Skymak 127 on the moon last night and was left feeling very underwhelmed in comparison to my SW 200P Dob. It is not the size of the image which is obviously going to be different,  but the clarity was nowhere near as crisp and clear. There was no dew or anything on the lens so I assume it must be the different type of scope.

[JamesF]

You have quite a drop in resolution going from the 200P to the 127Mak which perhaps won't help, but it may also be worth checking the collimation of the Mak.

James

[banjaxed]

Good idea James I will check it out, thank you.

[JamesF]

Oh, being a sealed tube containing a fair mass of glass the Mak can take quite a long time to reach equilibrium temperature-wise, too.  Before I had the observatory I used to leave mine outside as soon as I knew I would be likely to be using it that evening.

James

[John]

Cool down time might be the answer.

Also though, the F/6 200P dob is a pretty darn good lunar and planetary instrument.

 

[banjaxed]

Knowing the moon was going to be special last night I set the scope up at about 4 o’clock so it had plenty of time to cool down. Looks like collimation might be the answer.

Edited April 8, 2020 by banjaxed

[banjaxed]

10 minutes ago, John said:

Cool down time might be the answer.

Also though, the F/6 200P dob is a pretty darn good lunar and planetary instrument.

 

Good point John, the Dob was my first scope and has never disappointed me. Maybe I am expecting too much from the Mak.

[vlaiv]

I think it is probably collimation issue.

I have 8" F/6 dob and have been occasionally observing the moon (nothing serious, but had experience of what high power view of the moon looks like with that scope), and my new 102mm Mak made quite an impression on me after first use on luna. Image was very good / very sharp up to about x200 (1300mm scope and 5.5mm and 6.7mm EP). It did start to break a bit with 5.5mm but that was mostly due to seeing conditions.

 

[Captain Scarlet]

I collimated my SW mak 180 two nights ago. It was surprisingly easy and made an appreciable difference. I pointed it at Polaris at 450x mag, observed which edge of the (exquisite - seeing was good, I think) diffraction rings appeared the most squashed by putting my hand over the edge of the front of the scope to see where the obstruction appeared and therefore which colli screws were closest, adjusted it by trial and error until the "squashiness" got smaller and also changed orientation, moved to the new closest screws, and so on. I had the synscan handset in one hand on v fine adjust to keep Polaris centred as I made the changes.

Good luck...

Edited April 8, 2020 by Captain Magenta

[DavidJM]

I have the 200P and the MAK127, Mak is great on moon so would agree with collimating, the Mak is what I pretty much go to when having a moon session😀

[johninderby]

The 127 mak should be giving very sharp views of the moon. Not as much detail as the dob of course but should be a lot better than you are descibing. Possibly collimation was thrown off during shipping? In normal use shouldn’t need colimating.

[newbie alert]

34 minutes ago, Captain Magenta said:

I collimated my SW mak 180 two nights ago. It was surprisingly easy and made an appreciable difference. I pointed it at Polaris at 450x mag, observed which edge of the (exquisite - seeing was good, I think) diffraction rings appeared the most squashed by putting my hand over the edge of the front of the scope to see where the obstruction appeared and therefore which colli screws were closest, adjusted it by trial and error until the "squashiness" got smaller and also changed orientation, moved to the new closest screws, and so on. I had the synscan handset in one hand on v fine adjust to keep Polaris centred as I made the changes.

Good luck...

Is the mak like collimating a sct?

[JamesF]

15 minutes ago, newbie alert said:

Is the mak like collimating a sct?

Simpler, in a way, as you can't do anything with the secondary.

James

[Captain Scarlet]

18 minutes ago, newbie alert said:

Is the mak like collimating a sct?

yes and no.

No because on a SW-style mak, the secondary is a mirrored spot on the rear of the front corrector lens, and is therefore not adjustable. You're instead adjusting the primary mirror to get the diffraction rings right. And also no because the adjusters, at least on my 180, are each a pair of "push-pull" or "release-adjust-lock" screws (2 descriptions of the same arrangement).

Yes because the diffraction-ring process of doing the adjusting is more or less the same: find out which of the three screw positions is the appropriate one to adjust, and adjust accordingly.

 

Edited April 8, 2020 by Captain Magenta

[banjaxed]

Made an artificial star but can’t get far enough away to gain focus, I will have to try again when Polaris is in view.

[jetstream]

Its hard to best a good 200p dob... the central obstruction at over 30% starts to become an issue which can compound other things optics wise such as slight miscollimation.

[cupton]

I have the Orion version of your SW 127 and my scope does require some cool down time, otherwise the views are not crisp and I see a lot of heat waves in the eyepiece. Sorry, not sure if "heat waves" is the technical name for them or not. Depending on the temp difference between the house and outside it could be anywhere from 30 min to 1.5 hours that I leave it outside. Once acclimated though, the views are nice and crisp. Awesome scope on the moon and planets! Its funny how much of a difference it makes just by getting the temp right inside the scope.

Personally, I would try again with an acclimated scope just to make sure that was the issue before I even touched a collimation screw. But thats just me. I only own a Mak and a refractor, so collimating is not something I'm really used to. You dob owners could probably collimate with one hand tied behind your backs.

[banjaxed]

7 minutes ago, cupton said:

I have the Orion version of your SW 127 and my scope does require some cool down time, otherwise the views are not crisp and I see a lot of heat waves in the eyepiece. Sorry, not sure if "heat waves" is the technical name for them or not. Depending on the temp difference between the house and outside it could be anywhere from 30 min to 1.5 hours that I leave it outside. Once acclimated though, the views are nice and crisp. Awesome scope on the moon and planets! Its funny how much of a difference it makes just by getting the temp right inside the scope.

Personally, I would try again with an acclimated scope just to make sure that was the issue before I even touched a collimation screw. But thats just me. I only own a Mak and a refractor, so collimating is not something I'm really used to. You dob owners could probably collimate with one hand tied behind your backs.

Thank you for your suggestion but the scope was set up outside about 4/5 hours before viewing. Not sure if the 8” Dob has spoiled my expectations of the Mak.

[John]

I guess it is 200mm of aperture vs 121mm (the mak-casses work a little under their quoted aperture).

 

[cupton]

Apologies! I missed the post where you said it was set up at 4 o'clock and that it had plenty of time to cool down. Still only into my 1st cup of coffee here in the USA. I should of waited till cup number 2 before reading and posting. Hope you get it all worked out. The 5 inch mak really is a nice little scope that packs a lot of punch for its size.

[RT65CB-SWL]

6 hours ago, newbie alert said:

Is the mak like collimating a sct?

Unless it is a Meade ETX... they, (i.e. Meade), decided to put a flip-mirror housing. The only way to get to the collimation screws is to remove it... it is a PITA - even with my 're-modded' ETX105, (image below), I still have to remove the backplate - note: the blue discs are motorcycle/go-cart fairing washers and through them are the machine screws holding the backplate to the OTA.

 

With other 'Maksutov' telescope brands, I think the collimation screws are easily accessible. 

Edited April 8, 2020 by Philip R

[Avocette]

4 hours ago, banjaxed said:

I finally got to use my Skymak 127 on the moon last night and was left feeling very underwhelmed in comparison to my SW 200P Dob. It is not the size of the image which is obviously going to be different,  but the clarity was nowhere near as crisp and clear. There was no dew or anything on the lens so I assume it must be the different type of scope.

Just out of curiosity, did you buy your Mak new or used?

I bought my SkyMax 150  second hand, and wasn’t attentive enough in the buying visit to notice until I arrived home after a few hours of car journey that one of the collimation screws was loose. I presumed that it had shaken loose in the vibrations in the car, but now I’m not so sure. I also noticed (in comparing with a friend’s brand new 150) that there is a short baffle tube fixed to the secondary mirror which in my case seems to have been glued (perhaps clear superglue?) with a little excess adhesive visible, whereas there is no such glue visible in the new Mak. I assume that the previous owner dismantled my scope to clean the correction plate and possibly disturbed the baffle tube and had to reglue it. I researched long and hard before attempting to recollimate my scope, but finally I am reasonably happy with the result, again when I compare with my friend’s new one. However I would caution against touching the screws if you are not confident with the star test approach taken by Captain Magenta, and assume that your disappointment with the scope is influenced by lack of thermal equilibrium, before any comparison with your Dob. Even then bear in mind that comparison between two styles and sizes of scope is always fraught with subjectivity!
 

[Timebandit]

5 hours ago, banjaxed said:

I finally got to use my Skymak 127 on the moon last night and was left feeling very underwhelmed in comparison to my SW 200P Dob. It is not the size of the image which is obviously going to be different,  but the clarity was nowhere near as crisp and clear. There was no dew or anything on the lens so I assume it must be the different type of scope.

 

 

A Good 200mm reflector is really a cracking scope. Its until you use another scope then sometimes you do not realise how good the 200mm is . Great bang for buck and such a good aperture for most objects. That's why in my opinion it really does take some beating. If you do not get any joy with the 127 mak, then at least you know where to head next, another quality 200mm reflector.

 

 

 

 

 

 

[banjaxed]

With the help of an extender I managed to gain focus on my artificial star and to my eye it is very close if not spot on collimated. Thank you all for pointing out that my expectations were possibly too high compared to my 8" dob. This probably has given me aperture fever and I believe there is no cure. 😀

[mikeDnight]

Perhapse last night wasn't the best night to assess the 127 Mak's lunar performance, as the Moon was all but full. First quarter is best for spectacular detail in spring. Keep the scope cool and you may see a real gain in sharpness.