New to Astronomy

[taxman0720]

Hello Everyone. I am getting ready to make my first purchase and I am thinking about getting a Celestron Nexstar 6se as my first scope. I like the idea it is enclosed and should not have to worry about adjusting mirrors. I also like the simple mount and computerized goto. I eventually want to dabble in astrophotography and from what I read, it does a decent job. Before I make this purchase, I would like to get some input about this scope and feelings about other scopes that will give me more bang for my buck. I would like to keep it in about the same price range and it needs to be easy to load in my SUV and take it on the road.

I am looking forward to reading the information you have on this forum. Thanks for any help.

[Lady Fraktor]

Hello and welcome, glad you could make it over from AF

The SCT, Mak and refractors are normally good for holding collimation but SCT and Maks require a fair amount of time to acclimate.
They also have narrower field of views but work well for planetary, lunar, the brighter DSOs.
A SCT is considered a good general purpose telescope as it will let you do a bit of everything.

[helicon]

Hello and Welcome to the Forums!

[Shabadoo]

Hello and Welcome.

[JCINGA]

Welcome to the forum

That’s a great choice for a first scope. It will help you enjoy more gazing and less setup and understanding of the mechanics.

[Ylem]

The 6SE is a great scope!
It will show you a lot, and is quite portable.

That said, it might not be the best for AP (astrophotography)

[PapaFox]

Welcome and hello! I agree with others, it is a good first scope. I had a 5se and really enjoyed it.

[drock]

Welcome to the TSS. Enjoy the stars.

[pakarinen]

I was thinking the 6SE is a Mak. I see I was mistaken.

[Juno16]

Hi and welcome!

You will really enjoy that scope! Good to have you here with us!

Thanks,
Jim

[taxman0720]

Thank you all for the input and make me feel I am on the right track. As far as pictures are concerned, I am going to just start with short exposures of moon, Jupiter and Saturn. The good thing is this scope has an optional wedge you can buy so if I get really serious on astrophotography, I can get that. I look forward to becoming a part of this community.

[TCampbell]

Welcome!

I think you'll enjoy using that scope visually. It's a fairly compact scope so I think it fits your needs for taking on the road. Just a caution about astrophotography... I think you may find it has limitations w.r.t. astrophotography.

Astrophotography comes in "tiers" of complexity (and equipment demands).

At a simple level, a very wide-angle lens and a stationary tripod can take photos of the night sky (no telescope needed). You can also get a "tracking" head that attaches to an ordinary photo tripod and this will let you use a camera & ordinary camera lenses to take narrower images of targets in the sky. Even a "long" lens for a camera is considered "wide field" for astrophotography ... where most telescopes have much longer focal lengths than even long telephoto camera lenses.

Also, the moon is particularly bright and the exposure time is surprisingly short ... so tracking isn't really an issue for lunar photographs. But the NextStar 6SE has a 1500mm focal length. Using a DSLR camera with an APS-C size sensor (the most common sensor size for these cameras), the moon is a tight fit in the frame (it will fit but it will fill the frame of in the 'narrow' dimension of the camera image.) This is because the moon's angular width is typically about 1/2° across (just slightly more than 31 arc-minutes is average, but it's just a bit over 33 arc-minutes wide at perigee. An APS-C camera sensor on a 1500mm focal length scope would have a field of view just slightly over 36 arc-minutes across. So you'd really only have 5 arc-minutes to spare or about 2.5 arc-minutes of margin. This is why I say it'll be a tight fit. But the moon is bright enough that it's a fast exposure ... probably about 1/125th sec at ISO 100 in your f/10 scope.

Some planets make for good targets ... Jupiter, Saturn, and Mars tend to be favorites. Your scope will do well on these. Use a tiny sensor camera that can capture video and grab about 30 seconds worth of video frames. A ZWO ASI120MC-S is a popular camera for this sort of thing if on a budget (it's about $150 USD) and there are choices for those with deeper pockets.

Deep-sky objects require long exposure times (e.g. several minutes each) and this will be very challenging with your scope. This sort of astrophotography is very demanding for several reasons. Those "long" exposures mean that tracking accuracy is particularly important. It requires a solid mount and tripod (the mount is usually more important than the scope). The scope should be equatorially mounted (not alt/az ... although there are scopes that do use alt/az mounts and add a piece of gear called a field de-rotator). At long focal lengths these scopes require the use of an auto-guider to help keep the mount on target. This usually means either a second guide-scope or the use of something called an Off-Axis Guider adapter ... and a guide camera (a second camera). While the main imaging camera is taking a long exposure image (usually several minutes in duration per exposure) the guide camera is taking images every few seconds (e.g. 2-4 second exposures) of a star near that same object. It uses these images to determine how well the mount is tracking and it will send corrections to the mount to keep it on target.

It's easier to learn Deep-Sky astrophotography by starting at shorter focal lengths (e.g. 500mm or so) because it is a bit more forgiving about guiding accuracy.

Keep in mind the optical tube on the NexStar is attached to the mount via a standard "vixen" style dovetail rail. Telescopes are nearly universal in that they are usually attached to the mount via either a "vixen" style dovetail rail or a "losmandy" style dovetail rail. This means that, in the future, you could choose to acquire an equatorial mount with a compatible mounting saddle and move your existing optical tube to the new mount. A Celestron Advanced VX mount would be an example of a budget-priced mount that can do astrophotography so long as the amount of equipment on it isn't very heavy. This means you can certainly start with the Nexstar 6SE scope & mount ... and then just get mount more suitable for longer exposures when you are ready.

[Richard]

Welcome to TSS a SCT is a nice scope in the 5-6 inch area its portable and a decent scope not great at anything but probably the best all round scope, I dont do AP but my 5 inch on a go to SLT (Alt/Az) mount is my most used scope. As they say a good scope is the one you use , not sure of prices in your area but the best bang for bucks is a Dobs and so the same price you could probably get a 12 inch one , no comparison , but then its not a Go TO and certainly not that portable so its depends on your needs. Many have multiple scopes for this reason

[JayTee]

Hello and welcome.

That's a good choice for a first scope. Lunar and planetary images will be quite pleasing for you. Longer exposure deep-sky object astrophotography will be a bit problematic on this scope with its Alt-Az mount but the problems are not insurmountable (pun intended)!

Cheers,
JT

[taxman0720]

TCampbell - thanks for the detailed response and will have to do some more reading to understand everything said, but I want to clarify one item. I have a Nikon D5500 (crop sensor) and Nikon D750 (full frame) cameras. To do short exposures 30 seconds and under, which camera would be better to use?

[Markmjm]

Whatever scope you end up purchasing, I hope you enjoy it, and welcome to the forum.

[Thefatkitty]

I wouldn't mind having one of those; good for you! Welcome to TSS, as well

All the best,

[TCampbell]

TCampbell - thanks for the detailed response and will have to do some more reading to understand everything said, but I want to clarify one item. I have a Nikon D5500 (crop sensor) and Nikon D750 (full frame) cameras. To do short exposures 30 seconds and under, which camera would be better to use?

There are a few reasons why the APS-C size sensor camera (D5500) will probably be easier.

Keep in mind that the diagonal measurement of your camera sensors are roughly 29mm across for the D5500 and about 43mm (maybe 44mm) for the D750.

To attach the camera to the telescope you need a "prime focus adapter" (aka "nosepiece"). This adapter has a barrel that slides into the back of your telescope (typically a 1.25" or 2" barrel) on the front of it, but the back has the correct Nikon bayonet type mount for your cameras.

If you have a 1.25" receiver on the back of the scope, then this works out to 31.75mm ... but you lose a few millimeters for the wall thickness. So you probably have a clear opening of around 28mm across and this would result in perhaps a 1/2mm of vignetting in each corner *if* you use the D5500. But if you use the D750... the opening is much to small so you'll end up with extreme vignetting with the sides and corners of the frame not getting any light.

If you have a 2" receiver on the back of the scope, this gives you 50.8mm outer diameter... and after you subtract a few millimeters for the wall thickness of the tube you still have more than enough space for the full-frame sensor on the D750. BUT... the caveat is that these prime focus adapters are normally two pieces that are threaded together via t-threads. T-threads are M42 threads (42mm outer diameter) and after you subtract a bit for wall thickness you only have around 37 or 38mm inner diameter clearance ... which means you get vignetting anyway on a full-frame camera.

There are a few vendors that sell one-piece prime-focus adapters. So instead of two pieces that thread together with the T-threads... you have one solid machined piece and that means you get more than enough clearance inside.

That fixes the vignetting problem... but you still aren't out of the woods.

You'll also find that the telescope won't project a "flat" field 44mm across (telescopes that can project a large flat field suitable for use with full-frame or larger cameras are very expensive.) This means that even if you get around the vignetting problem, you'll likely find that the stars near the edge of the field don't look as good and you want to crop anyway. So... you may as well just use the D5500.