SCT vs Refractor

[GavStar]

In December I purchased my first telescope, a Celestron 6SE. I have alwatys been fascinated with space since I was a child but have never looked at the night sky apart from with my eyes. I went in with relatively low expectations and I have to say there have been exceeded. Jupiter was amazing in December - I saw the GRS and a moon transit as well as several cloud bands using a magnification of between 150 and 180. This month I had a great view of the Orion Nebula and the Trapezium which I knew nothing about until I got Turn Left at Orion for Christmas. The was very surprised when I could clearly make out the nebulosity.

So my interest has been well and truely sparked.

I've enjoyed "lurking" on several sites reading peoples views but this is my first post.

At the moment planets are my priority (can't wait for my first view of Saturn) and as such I have read that refractors give a crisper more satisfying view. Also the 6SE isn't particularly portable in my view particularly since I'm likely to go to the Canary Islands later this year and want to take a telescope with me. As a result (after a lot of "research") I have purchased a Televue TV85 with an iOptron Minitower mount (I really liked the goto on the 6SE, but didn't think the 6SE mount would be suitable for a refractor).

Obviously since I bought this scope its been cloudy, but I'm looking forward to a side by side comparison to make up my own mind.

In the meantime, I'd been interested to hear people's views on how the TV85 will compare with the 6SE and which targets I should do my side by side test on.

Thanks

Gavin

[damnut]

Hi There,

You have opened Pandoras boX!!. I Used to have 10" sct(which I used to take to dark sites!) and a 120mm frac....

Loved em both, the sct that you have should yield great planetary / lunar viewing and the frac will give better widefield views. You have the best of both worlds.

I currently have a 152mm frac and a 110mm mak. Cannot wait to get another big sct, even though the cloud is brewing.

You have lovely scopes, the best is the one you use the most!!.

Cheers

[Marki]

My first scope was an 8SE - I still use it from time to time, but hated the mount. I have a few fracs' now ranging from an 80mm APO to a 125mm achromat, mostly sat on an unmotorised eq5. The 80mm sits on a minitower II and is my grab and go (the minitower is absolutely excellent for a short tube). The 8SE tube might get used a bit more now I have a substantially beefier mount. The 6SE should be a good planetery scope though - long focal length for magnification.

Welcome to SGL by the way

[Rossco72]

I love my tv85 and tv102 scopes but in all likelihood your SCT will win on planets. With the tv85 you will be looking for more and more image scale and detail and the extra diameter of the cat will come into play.

For wide field low power the tv85 is a joy to use. Especially with a feathertouch micro focuser....

You have two good scopes which should keep you busy for a long time.

Cheers

Stuart

[DirkSteele]

The TV85 is a great little, portable refractor. You choose well. I have a 4" Apo that I take carry on on trips abroad, but to save myself the concern of how to power the set up, I go with a manual Alt Az mount.

The light grasp and resolving power of the 6SE is such, that it should still continue to outperform the TV85 on the planets despite the large (and contrast degrading) central obstruction. Assuming of course you keep the SCT well collimated. It is a very simple task, but if you are looking for an aid to assist in the collimation, follow the link below to a Duncan Mask that I previously posted (1st reply in the thread). However, the TV85 is very portable, will offer up far wider fields of view (so complementary to the 6SE), and you may think provide more pleasing view of open clusters (I do). And if you are at a dark sky site, you will be amazed at what the small scope can show you. In the desert of Oman (mag 6+ skies, 14/15 stars visible in M45 unaided for example), my 4" Apo was matching what my 11" SCT shows from fairly light polluted Hampshire.

http://stargazerslou...sk#entry1690591

Clear skies,

[E621Keith]

I agree with the comments above. If the 6SE is a good sample and well collimated, it's likely to out perform the TV85 under ideal condition for planetary observation.

The C6's long focal length and larger aperture also makes it easier to push magnification than the smaller TV85.

[John]

Someone did a review of a TV 85 and a C8 a while back which might be of interest:

http://www.cloudynights.com/item.php?item_id=734

I reckon the C6 will show more on deep sky objects and should show more planetary and lunar detail if it's a good one, cooled and the colimation is on the money. I say should for those latter objects because the TV 85 might just surprise you there !

[GavStar]

Thanks for all the comments and views. I think my 6SE is not too badly collimated but I will get it checked. I was of the impression that the TV85 should show a more contrasty view. Certainly the views I had of Jupiter from the 6SE were good but a little soft, I'm hoping that the TV85 may give a sharper image. I also like that TV85 will cool quickly and is more portable. I have got a Vixen Porta 2 for when I go on trips.

I've also treated myself to a 2" 30mm eyepiece specially for the TV85 for wideviews so looking forward to using that (but boy is it big and heavy!!)

Other comments from me:

I've just been viewing in my back garden in London so obviously the light pollution is pretty severe, despite this I've been pleased with the views. My brother lives near Dartmoor so I think he may be getting a visit from me and my scopes soon.

I've dealt with 3 astronomy dealers and they have all been excellent and supplied equipment very promptly. Makes a very pleasant change from dealing with other types of purchases!

Also pleased that Mak likes his Minitower. I originally got a Skywatcher Allview but the TV85 feathertouch focuser would hit the mount before it got to zenith, so am hoping no issues with the Minitower.

[GavStar]

Quick question for Stuart - how does your Tv85 compare with your TV102?

Thanks

Gavin

[ollypenrice]

If you offered me one or the other I'd take the TV85. I wouldn't hesitate for a nanosecond. I think that it will give a fine view of the planets and the comparison with the small SCT will depend on the night. On different nights with different seeing it will go either way. I know my own feelings, I use a lot of scopes, and I know that I always prefer refractor planets. What I have no experience of whatever is other peoples' eyes... so you may find otherwise.

But if you go to a dark site forget the damned planets!!! You've got them at home. From a dark site you can get into deep space, not your solar system back yard. Here the TV shows its class. It can give you wiiiiiiide field! With a good long FL Nagler (you wouldn't put anything less in a TV85!) you could drink in the entire Veil Nebula. I can do that in the humble Pronto, never mind the 85. They are big Milky Way vistas, there's the Rosette Nebula, there are so many lovely BIG objects which he short FL refractor can relish...

I had a 4 inch Genesis and now, with the budget guzzled by imaging, I just have a 70mm Pronto. It's surprising how well the Pronto does, so the 85 will be even better.

Olly

[RikM]

I would take the refractor as well.

I have been using a Pronto a lot recently and have been very impressed at the detail and contrast visible in Jupiter. The build quality is also first class. I have it on a TelePod mount and Manfrotto photo-tripod. Great grab and go scope, I only wish it a little more aperture. I think a TV85 would be an absolute joy to use.

[Rossco72]

Quick question for Stuart - how does your Tv85 compare with your TV102?

Thanks

Gavin

The TV85 gets used for imaging, with the TV reducer it's f5.6 and great for DSO's. I use the TV102 for visual on the TV Gibralter mount while any imaging run is ticking away.

The TV102 is a great scope, but TBH the difference over a Skywatcher 100mm f9 wouldn't rationally justify the price difference.

The TV85 is probably my most used scope at the moment.

Cheers

Stuart

[GavStar]

So because of the clouds (and having a nine week old daughter!), I haven't had a chance to do any further observing until tonight.

But it started off very clear this evening so I decided to have a go, and in particular try to see Saturn.

I used the TV85 on a Porta 2 mount, and the first impression was as a grab and go its much easier and quicker to set up than my 6SE - within minutes I was outside observing.

Saturn wasn't high enough at first so i had a look at my favourite so far, Jupiter. I gradually went through my Pentax XWs from 20mm to 7mm to 5mm, and then tried a Delos 4.5mm as well.

In summary, the responses above were right, the 6SE does give better planetary views than the TV85 due to it being harder to get high magnifications with the TV85.

Tonight I had a decent view of Jupiter, saw a couple of bands and the TV85 gave a sharp view, but it was smallish with little hope of getting more details such as the GRS. In December with the 6SE I had far better views, and easily saw the GRS and a moon transit. Also tonight the TV85 gave some colour on the edge of Jupiter - red on one side and blue on the other. I was a bit surprised about this - am I doing anything wrong here?

However, I found it easy to track Jupiter using the slo-mo controls on the Porta 2 so that was a definite plus.

I then got my 6SE out to do a direct comparison on Saturn, but unfortunately the clouds came in very quickly and that was that for the night. Saturn will have to wait again...

So it seems that when I'm travelling or want a quick look then it will be the TV85, but if I'm at home and got the time, then I think I will turn to the 6SE (the views in December were amazing). I do need to get a better finderscope for this - any suggestions?

Gavin

[E621Keith]

The TV85 red/blue colour on Jupiter is probably caused by atmospheric dispersion. It happens when an object is lower down in the atmosphere and your scope has nothing to do with it, so don't worry.

If you observed with your 6SE at the same time, you will see the same effect. You probably didn't notice it a few months ago when Jupiter was higher up.

[GavStar]

Thanks Keith - I was a bit worried that the red blue was CA so good that it's not.