Advice On Improving Astromaster 76EQ

[JonnyAlpha]

Hi;

I have picked up a Celestron Astromaster 76EQ (Details in another post) and have up until now had limited success. I have not yest set it up properly and do not have a Planasphere and I know to get the most out of it I need to follow the basics. I am aware of some of the limitation of this scope (from my other post) but in order to make the most out of this scope can anyone advise on the following:

1. I have read that a good Barlow 2 x Lens is recommended but should I get it in one of these accessories kits like this: http://www.amazon.co...62836819&sr=8-1 or this http://www.amazon.co...19&sr=8-3-fkmr0 these are probably at my limit of funding at the mo.

2. In my other post another gentlemen purchased the same scope and collimated it, how do I know if I need to collimate and if so how?

Up until now I have had some good viewings of the moon and have even managed the odd decent photo:

A pretty decent shot of the moon using the supplied 20mm Erecting Scope, taken with a Nickon Colpix (I Think).

But when it came to trying to photo a planet with a much reduced light source the effects were pretty poor.

Jupiter and its moons?!?!?!? Taken with the same camera I think? Using I think the 20mm eyepiece also, the picture through the eyepiece is much clearer but I can only just make out the banding and the moons are just white spots.

For photos I do understand that best results come with a web cam and frame stacking??

Anyway just thought I'd share.

[Stargazer_00]

Hi,

Is this the scope that you have?

http://www.currys.co.uk/gbuk/celestron-astromaster-76eq-reflector-telescope-08513325-pdt.html?srcid=198&cmpid=ppc%7egg%7eCameras%7e08513325&istCompanyId=bec25c7e-cbcd-460d-81d5-a25372d2e3d7&istItemId=qmqlqxl&istBid=t&ef_id=UTtNRgAAAdGtKIDT:20130309161358:s

It shows that it came with a 10mm and 20mm eyepiece.

A barlow lense sits between the eyepiece and the focuer. The barlow goes in like an eyepiece and then the eyepiece goes into the barlow like it would the focuser.

These have the effect of doubling the magnification of the eyepiece.

Magnification is worked out by dividing the focal length of the telescope by the focal length of the eyepieces.

Your telescope has a focal length of 700mm so your 10mm eyepiece will give 70x magnification and the 20mm eyepiece will give 35x magnification.

A barlow lense on the 20mm would basicially do exactly the same as the 10mm so that is pointless. The 10mm would become a 5mm and give 140x magnification.

All telescopes have a highest pracitcal magnification. This is usually the size of the aperture of the telescope in millimeters (its more complicated than that but this is a rough guide in most cases).

So for your telescope the highest practical magnification it would work at is 76x It would probably work OK up at around 90x-100x as well but the image would become dimmer and less resolved the higher you push it.

In my opnion you might be better off getting an eyepiece or two to get more ranges of magnifications. Perhaps a 7.5mm would be nice, this would give 93.333x (which is as high as I would push it). Maybe a 12.5mm as well, which would give 56x magnification.

These can be bought here: http://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-sp-plossl-eyepieces.html

The other items in the kits you listed are filters and other random things that arent used much. You would be better of investing in eyepieces as they will give you a broader range of magnifications and are transferrable to another scope should you ever want to upgrade later.

Hope that helps

[Delima05]

" collimated"

If that is the reflector you have- then collimated should be complete with the images you have posted. To check to see if a scope is collimated ( at least for reflector ) simplying looking side the aperture with no lens and seeing your eyeball + smaller mirror is a good reference that everything is up to date.

It appears to me that everything on your telescope seems up to pair and you probably won't get too much more out of what you are seeing now. I have a few different lens with a little better telescope and I wouldn't really suggest new ones. I'd suggest saving the money you'd spend in lens and invest into a more powerful scope.

[Lemzo]

Hi,

I have that exact same scope having received it as an Xmas present in Dec. This is my first scope and it has given me some great views for a starter scope. Although this is my first scope I have purchased a few new eye pieces with the view of upgrading the scope when autumn/winter comes back round.

I went for a 9mm Plossl and a 12mm Xcel LX. The 9mm has given me my best view of the Orion Nebula albeit on a very dark night. I use the 12mm for planetary viewing and the wider fov is great for Jupiter. A friend was recently in New York and brought me back a 2x Barlow and a 32mm plossl which is great for star hoping.

i fully agree with Delima05, if you can wait and budget is a consideration then I would also suggest putting the money towards your next scope as it will ultimately give your better viewing with the limitations of your existing scope. I can also appreciate that you want to get the most out of your current scope but even with the upgraded eye pieces I still find this scope to be limited in capability.

i intend to use it for the next 6 months to learn the constellations and get a better understanding of what I'm looking at then upgrade it and put my eye piece investment to better use.

Happy to answer any other questions if I can help at all.

[ianfiat]

I would get youself a Telrad (yes it will fit) and a couple of Vixen NPL eyepieces (suggest 15mm and 30mm)- these you can continue to use when you upgrade your telescope (thats what I did). The 10mm eyepiece that comes with the astromaster 76 is pretty awful to use and the red dot finder is worse than useless

[Stargazer_00]

on a smaller scope like this a rigel quickfinder would be better than the quite bulky telrad.

[JonnyAlpha]

Ok i think I am going to get an extra lens and there have been a couple of recommendations question is should I get a:

1. Vixen NPL 15mm.

or

2. Skywatcher SP Plossl 12.5mm.

Which of these will have a better (Clearer / Sharper / More Colour) image with my scope?

[ianfiat]

The Vixen

[ronl]

Try this site gives a good explanation of eyepieces, it might help http://www.swindonstargazers.com/beginners/eyepieces.htm

nice shot of the moon.

Good Luck and Clear Sky's.