Expensive disappointment - Am I doing something wrong?

[jtbesquire]

Hello everyone.  This is my first post.  I have recently begun stargazing and have quickly upgraded my celestron 127mm Newtonian to a beautiful Celestron NexStar 8SE (8inch Schmidt-Cassegrain, 2032mm focal length).  I have enjoyed using the 25mm plossl EP that came with it to see stars in parts of the sky that look empty to my naked eye, but when I turned to the planets, I was disappointed, as it seemed no better than my old 127mm scope.  My higher mag EPs were Rubbish, though.  So, I bought a Celestron X-Cel LX 7mm eyepiece.  Tonight, I finally got to see Jupiter.  Lined it up with the 25mm, and it looked sharp, all 4 Jovians clearly visible, and the two main bands, but it was small (as expected).  So then I excitedly switched to my new X-Cel and... major disappointment - the image was larger, but grainy and out of focus.  Worse, really than the 25mm image, only bigger.  Like taking a low-res image and enlarging it.  Am I doing something wrong?  Or is 7mm too much magnification for my scope?  Please help, because I'm pretty bummed out about this.

[Pig]

Hiya,

Your 8" SE should give decent views of Jupiter but a lot depends on the clarity of the skies, light pollution and the position the planet. Another consideration is your expectations may be set too high as the images in magazines are not representative of what you will see at the eyepiece from planet earth.... literally far from it. Jupiter is approximately 390 million miles away (630 million KM) so to see anything at all is pretty remarkable

A 7mm eyepiece is way too powerful with your scope for viewing Jupiter, giving a massive 290 X magnification. You really want to be around a 12mm (170 X magnification) & 14mm (145 X magnification). This will give you a nice blend between the detail you can make out and the size of the disc.

The quality of an eyepiece can also make some difference. However, this can get quite expensive  Your LX's are a very good starting point.

I just realised this was my 8,000th Post.... wow

 

 

[Joe12345]

Yes, a 7mm in your scope will be way too much power.

Because Schmidt cassegrain telescopes have super long focal lengths, you can get over the magnification limit quite quickly. Your 127mm scope would have been able to take a 4-5mm eyepiece but your Schmidt will only be any good at 10mm+ because it gives more magnification per aperture.

If you bought from FLO there's a chance they'll replace it

[cloudsweeper]

Yes, an 18 or 12mm EP would give more realistic and pleasing views.  If the seeing is poor, magnification just gives a larger, fuzzier image.

A focal reducer on the 8SE would give x51 with the 25mm, and x183 with the 7mm.  That would be better.  

Lower mag views of Jupiter can be nicer - say at x80 - x120 - so the view with your 25mm EP should be very good, albeit smallish.  

I would also think the 8SE should give more clarity/resolution/detail than the 127.  A Baader Nd filter might further enhance contrast for you.

Doug.

[RobertI]

Another couple of things to consider. SCTs take a long time to cool down (unless you store it in a shed) so it needs to go out at least an hour before you start observing. Insufficient cooling can result in planets appearing to 'boil' due to tube currents in the enclosed tube. The atmosphere is another factor and you can probably only know this by doing a side by side comparison between you 127 and 8SE at the same magnification. I have had a huge range of results on Jupiter with my C8, ranging from truly awful (making me think "what's happened to the scope?")  to mind blowingly good on a night with good seeing. I also beleive the bigger aperture means the nights of good seeing seem better and the nights of bad seeing seem worse. Finally collimation is vital. Hope that helps.

[Stu]

3 minutes ago, RobertI said:

Another couple of things to consider. SCTs take a long time to cool down (unless you store it in a shed) so it needs to go out at least an hour before you start observing. Insufficient cooling can result in planets appearing to 'boil' due to tube currents in the enclosed tube. The atmosphere is another factor and you can probably only know this by doing a side by side comparison between you 127 and 8SE at the same magnification. I have had a huge range of results on Jupiter with my C8, ranging from truly awful (making me think "what's happened to the scope?")  to mind blowingly good on a night with good seeing. I also beleive the bigger aperture means the nights of good seeing seem better and the nights of bad seeing seem worse. Finally collimation is vital. Hope that helps.

Totally agree with all this. Getting the cooling and collimation right is vital for good high powerimages with an SCT. They can be awful when not right, but excellent once you crack it. The do seem to be more susceptible to poor seeing conditions so keep trying on different nights, even if it looks crystal clear, the conditions are not always the best for high power work.

[Paz]

I agree with the comments about magnification. Also, how low or high in the sky was Jupiter when you were looking?

I was checking Jupiter out the other night with an f15 127 Maksutov when it was about 25 degrees high in the sky, so not ideal altitude-wise. I could see the two main equatorial belts but nothing more, and they kept coming into view and disappearing as the seeing changed. The detail maybe got slightly better moving from 60x up to 100x but it didn't get any better past that. This was with inexpensive plossl eyepieces.

[bish]

It has already been mentioned but a steady atmosphere makes the differences between a fuzzy blob and seeing lots of detail. Quite often you will get a mixture of good and bad if you are out for a while. X250 isn't too much for the scope but most of the time too much for the conditions. 

[brantuk]

All good advice above - I usually view Jupiter around 150x to 180x mag. It gets very grainy towards the horizon and anything higher than 200x mag so wait till it's high and do the eyepiece sums for best results. You will eventually learn how to look at stuff by scrutinising the planet - eventually detail starts popping out like the GRS and finer points in the banding. And remember - too much gain = lots of pain lol

[Mr Spock]

Seeing conditions and magnification will be responsible. There are very few nights a year you can use that kind of magnification on planets and almost never on Jupiter.

Try to keep as close to x200 as you can get for Jupiter but be mindful of the seeing conditions.

SCTs need to be fully cool for the best views. If you keep it close to outside temperatures then it should be good to go in half an hour or so. If it's kep inside then it will be 2-3 hours of cool down time - if the outside tempterature is falling rapidly it may never reach thermal equilibrium.

[timwetherell]

Some good advice here! And yes, so much depends on the seeing (stability of the atmosphere) Try to observe planets when they are as far above the horizon as possible. The atmosphere is a thin shell so looking along the horizon you're going through about 40 miles of it, straight up you're only looking through about 7miles! With good seeing, a high planet and a fully cooled 8" telescope magnifications of up to 400x can be used but 250x is probably more reasonable. One would expect Jupiter to look something like this with everything in your favour. Or on a bad night, little better than a ball of mush

 

 

[Klingon]

 I have been getting the best  visual on Jupiter at 3am when it is high in the sky, red spot, white and brown clouds clear with 14mm Delos x 200 mag. I do try at 10pm as it rises though the atmospherics affect the view, same as Saturn in the morning.

[Mak the Night]

Viewing Jupiter can depend a lot on atmospheric conditions, what time it is observed and just about every other variable lol! I think altitude can be one factor. Usually it would be best high in the plane of the ecliptic at least 40° or more. Yet I once saw incredible detail with it at around 145x in a twilight setting in the west (99.5 Azimuth) at an altitude of less than 12° with a 5“ scope. The background sky was blue!

I have very little light pollution to the west however as it is bordering the greenbelt. But I must have been looking through a lot of atmosphere. Possibly 20km as opposed to around 6km at the zenith. After that 20km of troposphere there is at least 50 km of stratosphere, 85 km of mesosphere, 690 km of thermosphere and 10,000 km of exosphere, let alone around 800,000,000 km of space (around 44 light minutes in distance at that time) before you reach Jupiter. 

So the light from the Sun has travelled at least an hour and three quarters to reach Jupiter to be reflected back to observers on Earth.  Wow! lol

[Highburymark]

Agree that 10-12mm eyepiece would be your best bet for Jupiter and Saturn on most nights. Your 7mm eyepiece will provide lovely high power views of the moon (although even with lunar, atmospheric conditions play a big part), and may be useful on few nights a year for planets when the seeing is perfect, but otherwise you'll need less powerful options. But if you're like me, a city dweller with limited choice when it comes to targets, studying the moon's mountains and valleys at high power is hugely rewarding - so I'd advise you don't sell the 7mm until you've had at least 4-5 nights of moon gazing. It's addictive. And some astronomers spend a lifetime doing it.

[hawklord2011]

I observed Jupiter for the first time last night with my 150mm newt. My max magnification is x150 with a 10mm and x2 Barlow. Whilst it brought a big old smile to my face as a first experience and the layout if the four visible moons was fab I did think it would be bigger in the eyepiece. I could see the two dark bands around the equator but given the size of the image I can't see how id have seen much more detail given the size of it, especially like that lovely sketch above. Any thoughts on the size in the eyepiece?

[John]

Jupiter is only around 43 arc seconds in apparent diameter. The field of view at 150x with your F/5 newtonian using standard eyepiece and barlow is .33 of a degree which is around 1,200 arc seconds. So you would be able to fit Jupiters disk around 28x across your field of view.

It might be the biggest planet but it's around 410,000,000 miles away so it appears rather small even with a telescope at high magnification.

The way to see more detail is to observe the planet carefully for long periods. You will then catch the short moments of really good seeing conditions (just a few seconds at at time usually) and thats when the more subtle details start to appear. There is a knack to it but it takes time to develop.

 

 

[The Flinty Fox]

As had been said already some very good advice from far more experienced observers than I, but I think that's the key,  experience and practice.

When I think back to when I first started out I can relate to how you feel, you go  out buy new things in the hope it will make a miraculous improvement to the views, which they do in a small way, but they are no substitute for practice.

I agree with the others that 7mm is probably too high. My best views of Jupiter has been around the 150 to 185 mark and even at that mag has still taken some considerable time and practice/learning to get the best from my scope and seeing conditions to get the best views I have seen.

So I say learn when the sky is at its best and learn to get the best from your  scope.

Hope this makes sense.

Paul

[jtbesquire]

Thanks for the overwhelming and helpful response everyone!  I guess I got greedy with the 7mm and was hoping to see Galileo-esque views of the cloud bands and spot.  I do have a 25mm plossl and a 2x Omni barlow that I may try later tonight.  Will likely hold onto the 7mm x-cel for a while and see if it comes in handy.  Otherwise, I guess I am about to drop another $70 bucks on a more realistic 12mm x-cel.  Thanks again all.  Hopefully I will have great stories to share soon!

[hawklord2011]

Great advice and support as ever I found this

whole thread really useful

[cloudsweeper]

5 hours ago, jtbesquire said:

Thanks for the overwhelming and helpful response everyone!  I guess I got greedy with the 7mm and was hoping to see Galileo-esque views of the cloud bands and spot.  I do have a 25mm plossl and a 2x Omni barlow that I may try later tonight.  Will likely hold onto the 7mm x-cel for a while and see if it comes in handy.  Otherwise, I guess I am about to drop another $70 bucks on a more realistic 12mm x-cel.  Thanks again all.  Hopefully I will have great stories to share soon!

The 12mm Celestron XCel LX  6-element 60 degree FMC parfocal is a nice EP, and not too dear.  It will give you x169 @ TFOV of 0.35 degrees in your 8SE.

With the f/6.3 focal reducer, it will give x107 @ 0.56 degrees.  

Doug.

[John]

Once of the great benefits of a good zoom eyepiece like the Hyperion 8-24 is that you can "fine tune" the magnification instantly to find the best setting for a particular object / viewing conditions.