Beginner Questions

[SteveTheEgg]

About a month ago I purchased a Celestron Starhopper 8 Inch Dobsonian. I have really enjoyed taking it out almost nightly. I have gotten bored looking at the moon and constellations the past few nights and have switched to looking at inner solar system planets. Venus is the easiest one to find, but I have really been disappointed with the amount of magnification. I can tell its a planet by its spherical shape, but the magnification is extremely poor. It doesn't really hold my attention for very long. If I can barely see Venus, how can I expect to see other planets or deep sky objects? My question is this: how can I increase my magnification?

[andyschlei]

Venus is a pretty boring object. Just bright and white.

Up higher in the sky is one of the best planets to view, Saturn. Saturn is fairly high in the sky at sunset, probably the second "star" you can see after Venus as the sky darkens. It is west of Regulus, the brightest star in the constellation Leo. With your 8" scope, you will have no problem seeing the Rings.

Jupiter is rising around 9:30pm, and is also a very impressive site, with 4 moons clearly visible.

In terms of magnification, you can approach it two ways: by shorter focal length eyepieces or buy barlow lenses. The magnification of a scope is the focal length divided by the focal length of the eyepiece. If you have your delivered 25mm Plossl and your focal length of 1219mm, the magnification you get now is about 49x. If you bought a 15mm or 9mm eyepiece, that would increase your magnification to 85x or 135x, respectively. A barlow lens increases the magnification by an integer factor. If you used a 2x barlow on your 25mm plossl, you would have an effective 12.5mm eyepiece and 98x magnification.

There are trade-offs with magnification. Images are dimmer, the movement of the air is more noticeable and it can be harder to find the object.

Hope this helps,

--Andy

[SteveTheEgg]

Hmmm can your recommend a good lens? Maybe a link?

And where is Jupiter? I couldn't find it. But Saturn was just gorgeous.

[Tucson_Tim]

Hmmm can your recommend a good lens? Maybe a link?

And where is Jupiter? I couldn't find it. But Saturn was just gorgeous.

Jupiter is in the east, right next to the constellation Scorpius. It is approaching opposition (next month I think) so now it is rising shortly after the sun sets.

If you don't have one already, get a star atlas. I have an old Norton's (and a newer version). I like it because it lists many things that you can see, but there are many others just as good, maybe better.

There are literally hundreds of "things" that can be seen with a scope like yours, but you need to take the time to learn the sky.

Here's a good one (I assume you're in the Northern hemisphere): M13, a beautiful globular cluster in Hercules:

http://en.wikipedia.org/wiki/Globular_cluster_M13

[andyschlei]

Hmmm can your recommend a good lens? Maybe a link?

I really like the eyepieces from Televue (http://www.televue.com/engine/page.asp?cat=2) and Parks Optical (http://www.parksoptical.com/index2.php?cPath=25&cat=Accessories). Televue is a premium brand, they have some of the most amazing eyepieces and barlows I've ever seen anywhere.

Where to buy? I'm a southern California guy, but with the miracle of the internet, you can get to my two favorite retailers, Scope City (http://www.scopecity.com/) and Oceanside Photo and Telescope (http://www.optcorp.com/). Just follow those links and don't hesitate to call, they will be very willing to help.

And where is Jupiter? I couldn't find it. But Saturn was just gorgeous.

Jupiter is quite south in the sky this year. It is very close to Antares, the brightest star in Scorpius. Here in Los Angeles, it rises at 8:26 and reaches its highest point or transit at 1:26am. I'm not sure where you are, but if you can see to the south to Scorpius, you should see Jupiter. It is much brighter and larger than Saturn.

Clear skies,

--Andy

[SteveTheEgg]

What do recommend as an easy to find deep-sky object that I can see with my 8"?

[redshifter]

I'd recommend a good star chart, that will give you the exact location of many deep sky objects.

For your 8 inch, check out M51, M81/82 in Ursa Major. There are quite a few galaxies in Leo that will show up in your scope as well. These are all galaxies and will require a dark sky location to see them.

For eyepeices, I've used/owned quite a few from the Orion catalog. These are worth checking out, if you don't want to spend the $ on the very good Televue eyepieces:
http://www.telescope.com/shopping/product/detailmain.jsp?itemID=73598&itemType=PRODUCT&iMainCat=6&iSubCat=36&iProductID=73598

http://www.telescope.com/shopping/product/detailmain.jsp?itemID=212&itemType=PRODUCT&iMainCat=6&iSubCat=36&iProductID=212

[SteveTheEgg]

What type of eyepiece is recommended? Nagler? Plossl? Panoptic? Radian?

Is there any image quality issues with shortening the eyepiece?

Is this worthy my time or money? http://www.optcorp.com/product.aspx?pid=1198-1199-9615

[andyschlei]

What do recommend as an easy to find deep-sky object that I can see with my 8"?

You could try the Ring Nebula in Lyra, or The Hercules globular cluster.

Try out Tonight's Sky (http://casazza.net/ts/), it should help you find objects.

[andyschlei]

What type of eyepiece is recommended? Nagler? Plossl? Panoptic? Radian?

Nagler, Panoptic, and Radian only come from Televue. They are great eyepieces, but rather expensive.

My Nagler 9mm was the first wide field eyepiece I bought. Awesome widefield views. I now have a 22mm Nagler that also provides great views, but requires a 2" rather than 1.25" adapter and diagonal. My 41mm Panoptic is a wonderful piece of glass. This collection of eyepieces totals over $1,000, so it's pricey glass.

The original 20mm plossl I got with my first 4.5" newtonian is an excellent eyepiece. My Parks 35mm plossl is a great utility eyepiece as well. With my 8" scope, these are the primary eyepieces I use.

Is there any image quality issues with shortening the eyepiece?

Not sure what you mean. If you use a shorter focal length eyepiece, you have greater magnification. The image will be dimmer, and the effects of moving air ("seeing") will be greater. Just because Saturn looks good at 20mm doesn't mean it will be good at 9mm.

Is this worthy my time or money? http://www.optcorp.com/product.aspx?pid=1198-1199-9615

Can't help with this one. The product has gotten good reviews, but I think you might do better learning the constellations with a planisphere.

HTH,

--Andy

[Tucson_Tim]

Here's another good site, the Sky and Telescope website, which shows a day-by-day look at the sky. It won't show you how to find open and globular clusters, binary stars, nebulae, or galaxies - for these you'll have to "star-hop" and the only way to do that is to use a good star atlas. As mentioned already, a planisphere will help with identifying the constellations.

There are a couple of threads on this forum that discussed different star atlases - search, you'll find them.

http://skytonight.com/observing/ataglance

[Dave Mitsky]

What do recommend as an easy to find deep-sky object that I can see with my 8"?

With the Moon currently waxing brightly, extended deep-sky objects are going to be rather difficult and unrewarding targets, even the best of them. Planetary observations are pretty much unaffected by moonlight, however, and there are a number of binary stars to observe as well.

You should consider picking up a good observing guide. Some of the best ones for novices include NightWatch: A Practical Guide to Viewing the Universe by Terence Dickinson, Phil Harrington's Star Watch: The Amateur Astronomer's Guide to Finding, Observing, and Learning About over 125 Celestial Objects, Turn Left at Orion: A Hundred Night Sky Objects to See in a Small Telescope--and How to Find Them by Dan M. Davis and Guy Consolmagno, and A Field Guide to Stars and Planets (Peterson Field Guides) by Jay M. Pasachoff.

IMO, the purchase of a planisphere (star wheel) and an introductory star atlas such as the Bright Star Atlas 2000.0 (http://www.willbell.com/atlas/atlas1.htm) by Tirion and Skiff or Sky & Telescope's Pocket Star Atlas (http://www.shopatsky.com/index.asp?PageAction=VIEWPROD&ProdID=1159) is a far better, and far less expensive, use of your funds than the new star identification gadgets from Celestron and Meade.

Browse http://www.skymaps.com/downloads.html for a free monthly star chart.

Some excellent astronomy freeware programs are available for download here (http://freeware.intrastar.net/astronmy.htm).

I post an astronomy calendar in this forum - http://www.bautforum.com/showthread.php?t=58102 - that includes monthly lists of DSOs and binary and multiple stars.

There are a number of less costly alternatives to the Tele Vue premium eyepieces, although they won't provide the same degree of field edge correction in fast telescopes that the Tele Vue Naglers and Panoptics offer. These include the Williams Optics SWANS and UWANs, the Meade Series 5000 SWA and UWA lines, and the Speers-WALER line. You may also want to have a look at the Burgess Optical/TMB Planetary Eyepiece line. These are first class oculars with a 60 degree apparent field of view and generous eye relief and are rather inexpensive.

Dave Mitsky

[Dave Mitsky]

Jupiter is in the east, right next to the constellation Scorpius. It is approaching opposition (next month I think) so now it is rising shortly after the sun sets.

That's correct. Jupiter will reach opposition at 23:00 UT (7:00 p.m. EDT) on June 5. At that time, it will shine at magnitude -2.6, subtend 45.7", and be visible for the entire night.

Dave Mitsky

[ColoRambler]

What do recommend as an easy to find deep-sky object that I can see with my 8"?

There's an embarrassment of riches here, though as at least one other poster mentions, they're harder to see in bright moonlight, so you may want to wait a week or two before trying these. With that in mind, some suggestions:

M57, the Ring Nebula. It's right between two bright stars in Lyra. Don't be afraid to bump up the power a bit on this one.

M13, a globular cluster in Hercules, right between two medium-bright stars in Hercules. This is one of the best examples of this type of object.

M4, a globular cluster in Scorpius, very close to Antares. This time of year, it's a little low in the early evening, but worth it -- it's a little easier to split into stars than M13.

M27, the "Dumbbell" Nebula -- it's quite large, though you do need a fairly dark sky to get the best view.

M11, a very bright open cluster.

[SteveTheEgg]

Do you guys recommend a 2x,3x, or 5x barlow? And if I buy from Televue will it fit my Celestron?

[Dave Mitsky]

Steve,

The answer to your second question is yes.

Usually a 2x Barlow lens is a better choice as long as one doesn't already have eyepieces with focal lengths that are multiples of two. The Tele Vue Barlow lenses are excellent and their telecentric Powermates, which have a four lens element design, are even better but are even more expensive, of course. If you want a "shorty" Barlow lens, the Antares/Celestron Ultima is a very good one, although there will be a little vignetting with long focal length eyepieces, a 32mm Ploessl for example.

Dave Mitsky

[SteveTheEgg]

Thanks, you guys have been really excellent. Thanks for running such a helpful and informative forum.

[SteveTheEgg]

With my alt-azimuth mount I have had an extremely difficult time finely adjusting the telescope vertically. The telescope "falls" making objects extremely difficult to find. It seems very top heavy. Is there any way to counter balance the weight to increase stability?

[redshifter]

Don't the starhopper scopes have slots cut in the sides of the tube such that you can slide the tube up or down slightly to correct balance problems?

[SteveTheEgg]

No there is not visible way to correct balance problems. It's extremely frustrating.

[schlaugh]

According to the Celestron web site the Starhoppers come with a "variable tension clutch system for proper balance and control in both altitude and azimuth." In their instruction manual you need to "tighten the focuser side handle to the desired amount of tension to properly balance the optical tube."

If you can't do that then it sounds like some kind of defect or maybe an assembly problem.

[JohnW]

According to the Celestron web site the Starhoppers come with a "variable tension clutch system for proper balance and control in both altitude and azimuth." In their instruction manual you need to "tighten the focuser side handle to the desired amount of tension to properly balance the optical tube."

If you can't do that then it sounds like some kind of defect or maybe an assembly problem.
"Variable tension clutch system" sounds much more sciency than "knob", but I think that's what it is. It sounds like you can't do anything to adjust the balance, but you can tighten the axis so the scope locks in place.

[redshifter]

But you can use that knob to introduce more friction on the altitude bearings, thus solving the balance problem.

[jouster]

Steve,

Note that you linked to a bracket for the SkyScout. The actual instrument is quite a bit more expensive.

[vorblesnak]

No there is not visible way to correct balance problems. It's extremely frustrating.

I use a small brick. Seriously. I saw this trick at the Oregon Star Party a few years back and have installed it on one of my scopes. Take a strip of velcro. Put one half on the weight, (the brick in my case), and the other half on the tube. When you over weight the tube with finders or eyepieces or whatever slide the brick along the tube until balace is restored, then set it on the velcro to hold it in that position.

Any simple weight will work.

David Davis
Toledo, Or 97391

And the brick gives you something to throw at those annoying yard lights.

[Kyle Edwards]

I use a small brick. Seriously. I saw this trick at the Oregon Star Party a few years back and have installed it on one of my scopes. Take a strip of velcro. Put one half on the weight, (the brick in my case), and the other half on the tube. When you over weight the tube with finders or eyepieces or whatever slide the brick along the tube until balace is restored, then set it on the velcro to hold it in that position.

Any simple weight will work.

David Davis
Toledo, Or 97391

And the brick gives you something to throw at those annoying yard lights.

I have also seen people balance dobs with large magnets covered in tape so as not to scratch the tube.

[anomaly]

Steve, in another thread you asked about software. Not sure if this is what you are looking for, but check these out. They are space/sky simulators that allow you to explore. And both are free :)

Celestia (http://www.shatters.net/celestia/)
Stellarium (http://www.stellarium.org/)