Celestron StarSense Explorer LT80AZ - mini review/first light

[bosun21]

I also found the LT70 to be reasonably sharp as well although as to be expected suffers from CA on the brighter targets. Once I removed the Starsense unit I gave it away to the scouts.

[sojourneyer]

On 10/07/2023 at 14:36, Stu said:

I picked up this starter scope at a discounted price from FLO (as a returned unit) largely to get my grubby mits on the highly rated StarSense unit; I didn’t have too much interest in the scope itself, it was just the cheapest StarSense scope I could find.

Having received it, I thought I might as well give it a go and do a mini review just to show what it’s like.

Current price is showing at £185 on FLO, down from £229. Not sure if this is just a promo price or ongoing, but it is quite affordable I would say. I received a neat but impressively large box, delivered with no drama.

Unpacking was straightforward, everything boxed neatly and securely. I didn’t need to follow the instructions as it was all very obvious; a new starter would likely have to do this though and they are very clear, taking you through assembly in simple steps with pictures and a description of each stage.

Being used to fairly solid kit in terms of tripods and mounts, I was surprised at just how lightweight the tripod and mount were. I would say this is probably the weakest part of the package as we will come to later on. Fitting the eyepiece tray does stiffen it up a little though, plus ensuring everything is tightened up properly.

The scope itself is a decently finished bit of kit. The objective looks good with decent coatings on it, bluish in tint. No collimation adjustments possible as you would expect at this price. The focuser is a lightweight affair with plastic housing but is perfectly functional and with no image shift.

Supplied accessories include a box-like erecting prism which did concern me; I would have preferred to see a simple mirror diagonal but I do see the point of making it useable as a terrestrial scope as well as for Astro. Two eyepieces are supplied; 25mm and 10mm, both lightweight but as will be seen, good enough as starter options. The RDF is a standard type device but I did find it all but impossible to align exactly, there didn’t seem to be enough range. Need to have another go at this. Lastly there was a very cheap feeling and lightweight Barlow. I did try to use this but couldn’t reach focus, again one for another night but I wouldn’t be too optimistic about the quality.

Mounting the scope was a little fiddly, needing to remember to fit the strut in place first before fitting the scope in place. Getting the scope the right way round on the mount also helps 🤪. Overall though quite straightforward if you follow the instructions 😊.

Fully assembled, the whole rig remains very light, a one hand (one finger!) lift out to the garden.

Once the scope was assembled, I turned to the reason for being here in the first place; the StarSense unit. This appears to be based on similar adjustment mechanisms as the NeXYZ phone mount although it seems more rigid. The unit was quite stiff to get into the fitting on the scope, but once pushed into place was firmly held with the adjustment screws.

Downloading the app was straightforward, and there are step by step tutorials to take you through alignment of the phone with the mirror and then aligning this with the scope itself.

In action, concerns about the mount were well founded, although it turned out to be workable and understandably cost targets have to be hit somewhere. I did a tap test side by side with my Tak on the ScopeTech and Gitzo tripod. Bear in mind the Tak was loaded with binoviewers and weighs around 6kg vs the very lightweight Celestron. The Tak settled within around a second, whilst the Celestron took around five seconds. Unfair test? Yes of course, but it demonstrates the differences between entry level and high end kit.

The StarSense functionality itself seems excellent. I don’t think I had my alignment with the scope quite right as it was a little off but overall it helped me find all the targets I was going for. Basically once enabled it tracks where the scope is, and when you select a target it highlights a path to push the scope along to get to the target. Once you get there, you leave the scope still for a moment and it plate solves to get an accurate location and when the cross hairs turn green you are in the right place. I found that it was slightly off (likely due to my initial alignment) but was close enough to allow me to easily find the target with the 25mm eyepiece. It did get more accurate over time but not sure why. The other amazing thing is that I was able to pick up the whole rig, carry it to another part of the garden and it still picked up straight away where the scope was pointed, no realignment necessary.

So, the StarSense technology seems excellent, and I will certainly mirror Johninderby’s method of mounting the unit onto a standard finder shoe to fit on any scope.

Back to the scope itself and what I saw…..

Double Double - I started off on this one as it was well positioned. The StarSense got me close with the 25mm and I found it quite easily. Popping in the 10mm gave me sufficient mag to attempt a split (x90). Focussing was tricky, not because of the focuser but because of the mount. It was quite wobbly and so focusing was a process of tweak, allow the mount to settle then go again; eventually I found a good focus and was pleased to say that I split both pairs. The even pair split more clearly whilst the uneven pair needed moments of better seeing. Generally star shapes were pretty good, although there was some spiking from the prism.

Polaris - the secondary was visible in the 25mm. Strangely going to the 10mm seemed to bring out the spike from the prism more which exactly coincided with the location of the secondary. I could still see it clearly once I realised this though. I will try the scope with a better diagonal and eyepieces to see what difference this makes, should be quite a change as the basic optics of the scope seem pretty good.

M57 - surprisingly good with the 10mm, a clear ring shape with the hole in the middle.

M13 - again, surprisingly good in the 10mm. With averted vision it showed a clear sparkling of stars resolving around it. Nice.

M81/82 - this was in a difficult part of the sky, over the streetlight which is shielded but still visible from the garden. Still, both galaxies were identifiable in the 25mm. Bearing in mind I had not got dark adapted it was quite impressive.

Izar - JUST about split in the 10mm. I’m sure with better diagonal and eyepieces it would be much easier.

Mizar - clear split on Mizar A and B as you would expect.

M11 - picked up in the 25mm then switched to the 10mm. This gave enough image scale to show the shape and start to resolve the tiny stars that make it up.

M17 - Swan or Omega nebula. Very faint nebulosity visible.

M16 - was just able to resolve the star cluster, no nebulosity.

M14 - small grey splodge visible.

NGC457 - this was easily found with the StarSense and showed very well in the 10mm. The two bright ‘eyes’ and shape of the little ET man was as pleasing as ever.

Double Cluster - nicely framed in the 25mm. Surprised how nice the stars looked. Outside the brighter stars, the spikes from the prism are not really an issue.

Overall I think this is a nice little package. If a new starter was using it in the same way I was last night, they would easily have been able to see a range of interesting objects. Experience helps of course, so it may be that the small misalignment and not knowing what to look for would have introduced some challenges but I think overall the StarSense makes finding things as a beginner far easier than just a finder.

The biggest challenge is the mount and tripod. The benefit is lightness and cost I guess, but the big negative is the wobbliness and resulting challenges with focusing accurately. Motion of the mount was also not as smooth as I would like so getting the scope to settled accurately on the target was a bit more hit or miss than optimum. I’ll have more of a play around with adjusting it to see if this can be improved.

Optically the scope seemed sound, a nice long focal length achro with CA well controlled (a result of the small aperture and f11 focal ratio). The eyepieces seem ok, and the prism not as bad as expected. Similar to my experiences with the ST80, using better quality accessories will likely result in a significant improvement in performance as the basic objective optics are sound.

I’ve now removed the StarSense and fitted it to a finder shoe so I can try it on other scopes, it’s currently sitting on Phyllis 😊, but I can imagine it will be very useful on Basil (the 8” f8, well it is very tall and spindly …. 😉)

I may do another unfair test vs the FC-76Q, 80mm f11 achro vs 76mm f12.75 fluorite apo. With decent eyepieces and diagonal I’m sure the Celestron will give a good account of itself. Need to find some rings for it ideally to mount them side by side.

Watch this space!

EDIT Pics of accessories added for the record…

 

 

 

[sojourneyer]

Very nice review. Thank you for sharing it with us.

 

Very nice review. Thank you for sharing it with us.

 

I purchased a used I purchased a used.LT 80 just for the cradle. Actually, the scope itself is not bad. But the mount was atrocious.

Using Velcro, I was able to fix the cradle around an 80ED and it worked fine