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menacegtr

FIRST TIME WITH THE STARTRAVEL-120 (AZ3)

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You now know the formula for calculating the magnification of a given EP  for a particular focal length (600mm). You now know the theoretical limits of your scope, x240 approx; and you know the limit imposed by seeing conditions, x200 approx.

What remains is to determine the magnification that you want when viewing the Moon. x120 will give you good detail, both for the Moon and the planets in general; x180 will give considerably more detail. It's up to you!

Then you have to decide how to achieve this magnification, either with a single EP or an EP combined with your Barlow. A 5mm EP will give you x120, but you could also get the same by using, in theory, a 12.5mm with the x2.5 Barlow. The nearest you will probably find is a 12mm EP.

Other options and combinations with the Barlow could be an 8mm EP. On its own it would give a userful x75, and with your Barlow making it effectively a 3.2mm, you will get x187.

My personal experience is that EPs under 8mm tend to be more demanding, especially in a scope such as yours with a fast focal ratio (f5), and many have quite limited eye relief. So I would probably go for something in the 8mm to 12mm range and use it with the Barlow.

This said, my favorite EPs for lunar observation are an older 5.5mm Meade 5000 which when used with a 1000mm refractor gives me x180, and an older 7.5mm Celestron Ultima, giving x133 or, occasionally x266 with a Barlow.

It really is a case of individual preference. There is a good selection of EPs in the 40 to 80 pound range which will suit your purposes very well. What is your budget?

Update:

Sorry if this is now a bit out of date - wrote it and tried to post in the morning - but just when I hit the "post" button, the server crashed! Anyway, parts at least may be useful!

 

Edited by Putaendo Patrick
Update

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@Putaendo Patrick Thank you for you apinion, I will take your advise and stick to 8mm and over. All I want to do is replace the included eyepices that come with the scope as many suggest they are there to get you going. I have also decided to get the OTA Skytravel 120mm and get the AZ-4 azimuth mount.

                                                                                      Regards. Dave:

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The 25mm is usable wouldn't rush to replace that one. I would go for 30/32mm and something like an 8mm. My most used eyepiece is a 16mm giving just 40x on my telescope.

As you can see choosing eyepieces a can of worms lol, probably why many say use what comes with a telescope before rushing to get more. There is also the design of eyepiece some other a soft eye cup some a flat top some users where glasses.

Read me all about eyepieces

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If you get stuck and need some local help setting up Dave, just send me a pm and we can arrange a phone call or meet up - I'm in your neck of the woods. :)

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@brantuk Bless you I have just noticed your from Leicester, I am at Old Dalby near Melton Mowbray if I get stuck it would be good to talk to someone who can help or even show me.  I will be getting the rest of the kit for my birthday 13/2/ so in the week after that i will be ordering the ST 120mm and the AZ-4. I was going to get the mount that comes with the scope but as many here have said its not that great, that's why getting good advise pays off, so I am looking forward to getting all the gear for my new hobby. Thanks again.

                                Regards. Dave:

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...wise decision.  The AZ4 will provide a solid, stable and lasting platform for the refractor. 

"'Another nice feature is the altitude and azimuth scales marked in one-degree divisions — a nice aid to locating celestial objects if you have a Palm or Pocket-PC planetarium program.'  Ade Ashford - Astronomy Now, Dec 08"

This is the manual for the AZ4, for both: the steel-legged and aluminum-legged variants....

http://www.opticalvision.co.uk/documents/163.pdf

The aluminum-legged version is lighter, of course, but it also sits closer to the ground when the legs are not extended, albeit with less stability overall perhaps compared to the steel-legged.  The 120mm f/5 has a short tube, but only in relation to its considerable aperture, and when compared to an 80mm.  One of the benefits of refractors and corrected-Cassegrains(SCTs and MCTs) is the ability to sit, and remain seated whilst observing.  Therefore, before purchasing either one, get out what you might anticipate as being your favourite observing chair, and a rule, make measurements, and according to the specs on the last page of the manual.  Several variables require consideration before deciding on which one to get.

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got all my gear, will report back after testing

Edited by menacegtr

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I'm late to this thread but I just wanted to say , Portability is something to consider when choosing the right scope , especially if its to be used for terrestrial as well as night time use . I had a 180mm mak which is a brilliant scope but notice I wrote the word "had". It sat in my wardrobe with my EQ5 for many weeks as setting up and transporting it became a real chore from my light polluted garden . Now I have a very small WO z61 which I use for both visual and Photography ( not that I've had too much success with the latter yet). The point is , I love those short tube refractors that you can just pick up and go. Don't get me wrong , I would also love an observatory in my garden and a permanently mounted giant reflector but that's not an option , so , I choose to have the best scope set up for my needs . And as we all know , the best scopes are the ones we use !

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Yes agree with all the above re hold your horses

biggest thing will be getting used to your scope and what you end up enjoying the most

planets and moon are one thing but limited in the amount of time viewing because of there nature etc

deep sky is great and avalible most of thd time if not cloudy. Your scope will be better suited to DSO so save the money on lenses for the moment and upgrade as you go. You may find you can then get a dedicated planet scope after a while and utilise the eye pieces you get for both. 

A polution filter is a must and a decent barlow as well. The 25 mm that comes with Skywatcher is fine may be upgrade the 10mm. I got a 9.5 wide relief which helps a lot it was about £80

i have the smaller 102 travel and mak 127

both great value and easy to use 

also remember what you see will be different to images in the magazines. Maybe get a phone holder and have a go at imagining something to do when not able to view

😀 

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