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Review of NexStar 4SE


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By chance a work colleague asked me to take a look at his NexStar 4SE and see if I could make sense of it, he's had it 2 years but struggled to get on with it. I was happy to check it out and borrow it over the weekend. Also I thought it be good to do a direct comparison with the Skywatcher 250 px, as both are similarly priced and I was seriously considering the NexStar when choosing a good beginner scope. At the time last summer I was tearing my hair out trying to decide between a variety of scopes. The 'veterans' on here recommend a Dobsonian as a first scope with much more emphasis placed upon optics over GOTO. I might as well cut to the chase, they were right and I am forever indebted to this forums advice. I enjoyed using the 4SE over the weekend but it firmly reassured me I'd made the right choice with a 'manual' tracking 10" Dob. Inevitably there's going to be a few negative comments aimed at the 4SE in this review, these are my own thoughts and I know there are plenty of happy 4SE owners out there! Note I observe from a typical edge of town estate. I have street light invading my garden and have to make do with looking South - East - North, anything West is blocked by trees and lights. My limiting magnitude (through the Dob) is approx 11-12 depending on seeing.

Let's start with some positives:

• Great Portability - The scope itself is a pocket rocket, it's compact enough to fit into your rucksack, albeit you then have to consider the tripod! It sits nicely on the shelf at home unobtrusively and weighs virtually nothing.

• Simple - Screw the scope to mount, level the mount, power up, align, observe

• Cooling Time - Relatively quick in comparison to other scopes

• Kit Lens - The 25 mm Celestron X-Cel eyepiece is better than the eyepieces most other beginner scopes come with

• Object Database - An excellent array of celestial targets, neatly divided up into good sub categories. I really enjoyed selecting a constellation and then letting the scope list all the noteworthy double stars, variable stars, Caldwell, NGC objects, etc. This was a great tool to exploring a constellation in depth

• Mirror Flip - Very easy to do some good basic astrophotography via the built in camera attachment port and mirror flip

Setting Up

It made a very welcomed change carrying the 4SE out to the garden, I'm more used to doing the 'bear waddle' whilst carrying my large Dob outside, no need to move the sofa, no disapproving tuts from the OH, no accidents (the dob has scared me from an unfortunate head butt!) a breeze to carry around. The mount is a little awkward to maneuver when lengthening the legs due to its unbalanced top heavy nature. This also made leveling a slight pain too; I noticed to get the best leveling the scope must be attached first. Why they didn't build the bubble spirit level into the mount I don't know, it could've easily fit into the top of the battery cover, there's no need to carry another small piece of equipment that you'll easily misplace in the dark, plus it should glow in the dark. I didn't bother with the batteries and used a 12v adapter.

Alignment

I read up on the various pitfalls and problems people were having on SGL, I made sure I read the instruction manual thoroughly and crucially made sure the mount was level. First off was to align the finderscope, an easy enough task to do. I used Jupiter as my reference and within 1 min had the gas giant perfectly centered in both the viewfinder and eyepiece. I must state that I’m very confident with the locations of stars; I know my way around and thus don’t need to rely on the automatic alignment options. I thought I’d try and use the scope like my friend would...i.e. with no knowledge of the night sky, so this put me at the door of ‘SkyAlign’. I choose 3 stars at varying heights with good distances between them – Castor, Saiph, and Sirrus. To my amazement SkyAlign worked first time, or so I thought! I dialled in Jupiter and was dismayed when the scope slewed to a point in the sky a complete 180 degrees from Jupiter! I reset the scope and retraced over my steps, ticking them off against the instructions in the manual, triple checked my location, date, and time data. I made sure I hadn’t fallen foul of all the pitfalls such as date being in US format. I tried again, and again it was successful but couldn’t then slew correctly to the correct target. I checked which alignment stars it’d registered in SkyAlign and to my dismay it’d listed the wrong ones! For instance in place of Saiph was Almach!!! So with that method binned off I went for a manual two star align. It worked first time without fail and subsequent times thereafter. I wish there was an option for three star alignment that didn’t rely on SkyAlign being ‘successful’ first.

Once it was locked in and working, I then began to test the GOTO’s accuracy. I have no experience with GOTO tracking so maybe my expectations were unrealistic. I made sure my alignment was spot on by using high powered EP’s when centering the alignment stars, this gives less margin for error. I chose the star clusters in Auriga as a place to start. Dropping down to a 32 mm wide FOV eyepiece I thought it’d be a doodle for the scope to slew to M37, it found it okay, albeit very off center (bear in mind I was using a very wide FOV eyepiece), I had to position it in the center with a few dabs on the hand controller, not bad but I knew what M37 looked like, I think others might struggle with less obvious objects unless they’re directly in the center. Throughout the evening I tweaked the alignment stars and increased the accuracy of the GOTO function. Although it worked in the general sense; it consistently failed to center any object and usually placed them off center towards the edges of the FOV. With EP’s smaller than 15 mm I often found the object wasn’t in view and I had to nudge the scope around a little to find the target. No problem for me, but for a beginner it’d may be pretty disheartening to see an empty view as they may struggle to find what they’re looking for.

The ‘sync’ option performed well and gave me some great views of Jupiter, keeping it firmly centered in the 7 mm EP for a good 30+ mins. This I can’t fault the scope on, it was a pleasure to not continually need to nudge the scope along.

Optics

For a small aperture telescope it did pretty well picking objects out from my garden, even managed to pick out the Crab Nebula (M1) pretty easily which impressed me. I found it performed better on the brighter objects, especially planets and double stars. DSO’s were viewable, albeit very faintly and often with no detail, a grey wispy smudge was typical. I felt the view through the scope was a little dark and cloudy, I checked the optics for dirt but no improvement. It may be that I’m used to the brighter views the Dob affords me and I’m being unduly critical. The view is much crisper/cleaner through the Dob in comparison, that's to be expected given the disparity in mirror sizes. I thought it be good to do a star count on M37 using the same EP in both, I selected the 25 mm X-Cel eyepiece that came with the 4SE. I counted 36 stars clearly in the 4SE, with the Dob I gave up counting at 80. I think what lets the 4SE down in that respect is the focuser isn’t fine enough, and the mount has a little wobble in it which makes it hard to finely tune the focusing.

Final Thoughts

I did like the 4SE, as a first scope I think it’s a worthy choice, it’s simple, very portable, and isn’t too much of an assault on the finances. I enjoyed zipping around the night sky with ease and liked the features in the handset. I am critical though of the GOTO function and feel it could be improved upon to give a better first impression for a beginner, the optics were adequate considering the majority of the money goes into the mount. My friend struggled with it and found it a little daunting for some reason, maybe a little more homework on the night sky would’ve alleviated their concerns. All in all it’s one to consider.

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Thanks for the nice write up. It really sums up to advantage of a dob. For the same money as a 4" GOTO, you can get a 10" fuzzy buster.

For the 3 stars Sky Align, it's best to pick three stars at different elevations and with a wide separation between each star and the next (read: opposite sides of the sky). Something like Mizar, Rigel and Shedir. Castor, Saiph and Sirrus are too close together. Ideally, the scope should have gone round at least 270 deg when you finished the alignment.

I think this post will be better in the members equipment review section.

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When i first got back into astronomy this was the scope I went for, it is a cracking little scope, I out grew it very quickly though.

The only thing is i feel that the skymax 127 is better value overall, more apature and £20.00 ish cheaper, but not in sexy metallic orange !

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