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Автор Тема: A few questions...  (Прочитано 11381 раз)

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Steve1976

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A few questions...
« : 06 Февраля 2010, 10:09:53 »
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Hello everyone!

First off I'd better introduce myself. I'm Steve from Edinburgh in Scotland. I've been living in Poltava for just over 2 years. My russian is so-so, not too bad but not too great and my ukrainian non-existant! I am a complete beginner to astronomy but am keen to learn so any advice you can give me would be greatly appreciated.

I do have a few specific questions which I'm hoping someone could help me with -

I'm thinking of buying my first telescope - SKywatcher Maxview 127 with EQ3 mount (matsukov-cassegrain). Can anyone recommend this scope? Any problems with it? My one concern is about collimation (коллимация). If I understand things correctly it should not really need collimation much compared to say a Newtonian reflector but when it does it could be a bit tricky - is this correct? Does anyone have experience here of collimating a matsukov-cassegrain?

Also, does anyone have any tips on making a dew cap / shield (роса)?

And lastly! I would say I'm getting used to Ukrainian winters here more and more but it's still a nightmare for me! Do you guys/girls still do astronomy in the winter? How would such low temperatures affect an actual telescope?

Any help greatly appreciated!!

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Mott

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Re: A few questions...
« Ответ #1 : 06 Февраля 2010, 10:45:05 »
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HELLO Steve

First, what was the reason for you to get Maksutov scope? Do you have any special preferences in visual observations (planets or deep sky objects etc.) or you are thinking to go for astrophoto?  This is probably the of the basic important question from the very beginning.

Second, Maks are normally pre-collimated  by the manufacturer but if you are forced to do this by you own then it is a bit more complicated compared to Newtonians.

Dew casp: the lads will wake up soon (today is Saturday) and I'm pretty sure they will provide you with a number of links to the home made dew shields.

Winters: this winter is probably the most tough for the last decade. My personal experience - observations with Newtonian and refractor scopes within the ambient air temperature: -13 to -15 C. (if it is not windy then you should get dressed for the temperature of about - 25 to - 30C then). IMHO If the temperature is lower than -15 C then stay at home over the nights and enjoy  this astro-forum contacts and discussions.  :)
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Tempora mutantur et nos mutamur in illis

Андрей-Чечако

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Re: A few questions...
« Ответ #2 : 06 Февраля 2010, 12:28:31 »
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Hello Steve!
I will be in Poltava, February 17-19 at the exhibition. Incidentally, in Poltava is astronomy club. We could meet. Andrew
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Steve1976

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Re: A few questions...
« Ответ #3 : 06 Февраля 2010, 13:50:57 »
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Thanks for the replies!

I was thinking a Maksutov-Cassegrain as I read in a few places that they do pretty well on the planets (maybe not so well as with a refractor) and ok in deep space too (maybe not as good as a reflector). I was thinking they perhaps offered some sort of compromise or middle ground between a reflector and a refractor. I know they are quite compact and portable and I also suspected that they might not need as much collimation as a reflector. I was a bit put off Newt reflectors to be honest as I read that they need a lot more collimation. It's not that I mind a little extra work now and then it's just that I don't know how complex a process it is having to fine-tune one of these things having never done it before! I am potentially interested in astrophotgraphy but perhaps a little later on. I think I would need to buy some motor drives for the Maxview but I already have a pretty decent manual SLR camera.

If a Maksutov-Cassesgrain did need collimation is this something that the average half-intelligent person could do or would I need some extra help eg from the manufacturers or such-like?  I don't mind a more complicated process as long as I could potentially do it. I just don't want to buy a scope which only the manufacturer or some professional can collimate - that would be a big pain!

Is there anyone with experience of such as a scope in the Poltava Astronomy Club that could help me collimate it in the event that I got stuck?!?

Also, would you guys be able to recommend any good scopes?

Андрей I would be very glad to meet with you when you are in Poltava, that would be great (please remember that my russian is only so-so!)
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Андрей-Чечако

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Re: A few questions...
« Ответ #4 : 06 Февраля 2010, 15:38:24 »
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Андрей I would be very glad to meet with you when you are in Poltava, that would be great (please remember that my russian is only so-so!)
I learn English and if you learning Russian - we it will be something to talk about))

Цитировать
Also, would you guys be able to recommend any good scopes?
I recommend TAL 125
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Steve1976

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Re: A few questions...
« Ответ #5 : 06 Февраля 2010, 17:42:54 »
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Yes I think it's a good idea to meet so just let me know where and when etc etc

How much does a TAL 125 roughly cost and where is it possible to buy them? The 125 is a refractor, is that right?
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Yvk

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Re: A few questions...
« Ответ #6 : 06 Февраля 2010, 19:07:27 »
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Hi Steve,

Collimating these Skywatcher Mak-Cas'es is not a big problem.
If it was Ok from the factory/seller and just gradually went out of alignment because of a _lot_ of transportation and ocassional rather rough handling it can be easily put back by scope owner. Though you will need some patience as the work is a little bit tedious and may take upto three hours.

I did it several times for my scope and the first time occured after maybe two or more years of owning and using it. I started to think about collimation because I wanted to disassemble the scope for some reason (which I don't quite remember now ;D) so I needed some knowledge on how to put it back together as it was. I found russian translation ( http://www.astronomer.ru/library.php?action=2&sub=2&gid=27 ) of the article by Otto Piechowski "Collimating the INTES MK67 / ORION ARGONAUT 150" http://astro.geekjoy.com/scopes/MK67_collmation.html  The collimation method is well explained and there are some real photos of what out of focus star may look like in Mak-Cas. I put several hours to studying ringy pictures shown by my scope and comparing them with descriptions and photos in the article. There was no hurry so the studiyng was actually spread over a month or two. Then I finally decided that there aint no magic and went on with dismantling.

Method described in article involves collimating secondary mirror but in Skywatcher Mak-Cas'es only primary mirror can be collimated - this simplifies things. There are six screws on the back cover three of them are pushing, three - pulling. To reach the screws you will need two small allen wrenches (I don't know their sizes just bought a set and selected suitable ones). You will need to point a scope to some star (Polaris is good - it doesn't move :) ), so maybe the best place is to do it outdoors (also in terms of atmosphere stability) but the first time I collimated I did it from balcony and used mount's tracking instead of pointing to Polaris. You will need quite high magnification well beyond any reasonable observing magnification - I used 6mm eyepiece which alone gives 2D (250x) together with 2x barlow lens - so be prepared and plan your accessory set accordingly.

Hope this helps. :)
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ladyinblack

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Re: A few questions...
« Ответ #7 : 06 Февраля 2010, 21:10:05 »
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Excellent mate, thanks for that. It's put my mind at rest that its a process which is at least possible even if its tricky. If something goes out with the secondary mirror I assume it would be a case of sending it back to the manufacturers for repair (if still within warranty period)?
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Steve1976

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Re: A few questions...
« Ответ #8 : 06 Февраля 2010, 21:13:20 »
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Sorry Ladyinblack's mesage was actually mine (my wife had logged on under her account)!
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Yvk

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Re: A few questions...
« Ответ #9 : 07 Февраля 2010, 14:14:45 »
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Цитировать
If something goes out with the secondary mirror I assume it would be a case of sending it back to the manufacturers for repair (if still within warranty period)?

Not much that can go out of order. Secondary mirror is just an aluminized reflective spot in the center of the front meniscus lens (much cheaper than a separate adjustable cell). If it is not some obvious mechanical problem it might be difficult for a novice to determine something is wrong with namely the meniscus or the secondary. It would be great if you find someone near your location with experience who could look into your scope and share an advice.
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Steve1976

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Re: A few questions...
« Ответ #10 : 07 Февраля 2010, 17:21:01 »
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Great info there! You guys have been a big help. I'm really glad I found this site!
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Roman K.

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Re: A few questions...
« Ответ #11 : 09 Февраля 2010, 00:07:36 »
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Is there anyone with experience of such as a scope in the Poltava Astronomy Club that could help me collimate it in the event that I got stuck?!?
Hello Steve. I had somehow missed this thread, so only now have seen your messages.

About the scope: unfortunately I can't provide any sufficient help with collimation

About the astronomy club: yes, it is an astronomy club here, I'm the coordinator of it, so you can contact me for any questions right here on the forum via PM ("Личные сообщения") or by phone.
More to say... We're going to gather our first meeting on Sunday (Feb.14), and we'll be located at gravimetric observatory. Though I don't know whether this info will be useful to you or not, if you say your russian isn't enough good. But anyway we can meet on any other day.

About the winter:
Do you guys/girls still do astronomy in the winter?
Yes, we do.  :gigi: My personal record low while observing is -23C. What I can say... It isn't very cold if you're dressed properly.

Best luck,
Roman
« Последнее редактирование: 09 Февраля 2010, 00:28:46 от Roman K. »
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Александр

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Re: A few questions...
« Ответ #12 : 09 Февраля 2010, 22:35:56 »
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Hello, Steve and Lady in Black!

I'm from the astroclub in Dnepropetrovsk and plan to be at the Poltava's club meeting on Feb., 14. There will be Oleg Kryklja from Krasnograd (Kharkov's region) as well and he has large experiance in constructing telescopes (he has a hand-made parabolic mirror actually). So I think that the day is a very nice opportunity for you to solve your three problems.

With respect,
« Последнее редактирование: 09 Февраля 2010, 22:42:04 от Александр »
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Ясного неба!

Александр Прокофьев.
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Roman K.

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Re: A few questions...
« Ответ #13 : 10 Февраля 2010, 20:18:41 »
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(...) and plan to be at the Poltava's club meeting on Feb., 14. (...) So I think that the day is a very nice opportunity for you to solve your three problems.
Just to add. If your plans will change, Steve, and you will have a bit of time to meet us, probably the best time will be near 5-6PM when our meeting will be over.
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Steve1976

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Re: A few questions...
« Ответ #14 : 11 Февраля 2010, 09:08:40 »
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Thanks for the invitations! With it being Valentines day and me also having to give a few English lessons which I can't cancel it will be difficult for me to come along to the actual meeting. I will be able to make other meetings in the future however and I really want to come and meet you guys. But if I can think of something I will try and make it along for 5-6 on Sunday so hopefully see you all then!
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targz

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Re: A few questions...
« Ответ #15 : 11 Февраля 2010, 15:42:43 »
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 Hello Steve. To be honest mak's from china not best choice, especially because alot of newtonians and refractors are tested and theres a little chance to get really good optics. And for photo need to start from hard mount. If u haven't huge cashe box u could also try TAL-150k - cloudynights dot com have some rewievs with really bad alignment, but most ppl report good quality and say its has really hard alignment wich they dont touch 1-2 years even after many riding on our offroads. Some ppl who modified it for photo use have best quality images of deep-sky objects and holds good enlarges like 2-3d wheres d (for 150k = 300x(2d)). Also u can try look at www.npzoptics.com and directly talk to manufacturer. Also u have a chace to find APO lens http://lzos.ru/en/ so 100mm apo lens equialent to 125 achro lens and it will be really good astrograph in any reason.
 Best regards.
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Steve1976

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Re: A few questions...
« Ответ #16 : 11 Февраля 2010, 20:02:52 »
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кошмар! I just got the Mak-127 yesterday!
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LifeIsGood

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Re: A few questions...
« Ответ #17 : 11 Февраля 2010, 21:40:07 »
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Congratulations! Don't panic.  ;D People here tend to be overly alanytical, often forgetting that the best telescope is one that you use the most. 127 mak is lightweight, portable and still can provide great pleasure! :binolook:
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Grew

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Re: A few questions...
« Ответ #18 : 11 Февраля 2010, 22:22:05 »
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  ...mak's from china not best choice, especially because alot of newtonians and refractors are tested and theres a little chance to get really good optics...
I don't agree. It is a reasonable choice for a small money.  I congratulate!
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Roman K.

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Re: A few questions...
« Ответ #19 : 11 Февраля 2010, 22:30:02 »
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I just got the Mak-127 yesterday!
Congratulations! There is always a better scope you could buy, until you get 30" Dob. Perhaps...  ;)
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