Celestron StarSense Explorer LT80AZ - mini review/first light

[Stu]

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…

 

 

[Second Time Around]

Excellent and comprehensive write up!

Regulars will know I'm a great fan of Starsense Explorer, especially for beginners.  Indeed, having bought the 70mm for two of my grandkids I promptly bought another for myself.  This was just to get the SSE unit, that I adapted to fit standard Synta finder shoes.  I then donated the scope to a pair of beginners.

From reading Stu's report I suspect that the 70mm might be better as a scope, purely as the lighter weight and shorter tube makes it less wobbly (the mount's the same it seems).  It wouldn't resolve as close doubles of course, but would have a wider field of view - useful for the Pleiades for instance.

Thanks again, Stu. 👍

Edited July 11, 2023 by Second Time Around
Spelling.

[DaveL59]

Welcome to the club Stu 🙂

It is surprisingly good as a unit using a mobile phone isn't it. I have the LT70 version and tbh it ain't a bad lightweight scope, just the tripod and mount but I swapped those for wood legs and a sturdier yoke which made it a lot more stable and didn't cost me much to do. I also fixed the slop in the focuser with some teflon tape and added a tasco motor focuser, much easier than trying to hit focus with it wobbling about.

That rig is now with my daughter and grandkids to enjoy in SELondon tho they've not had much chance with doing a lot of work on the house etc. I did supply it with a proper star diagonal and a zoom eyepiece so they'd get an easier and better experience.

[RobertI]

Nice first light report Stu. Very much mirrors my experience with the 70mm version. I was planning on doing a side by side test of the scope against my Zenithstar 66 out of curiosity, but not managed it yet. But like you I was surprised how easily I found, and could see, some fairly dim objects. Clearly no issues with the optics, so I popped it in some rings and put it on my mini-giro and is nice and solid. I have been finding the sticky grease in the focusing rack a huge pain as I keep accidentally touching it - I may remove this. 

 

[Second Time Around]

Like Dave I upgraded the scope I gave to my grandkids. 

I added a Celestron star diagonal, a 32mm Plossl, a 9-27mm zoom eyepiece and a decent 1.5/2x Barlow.

I also bought a secondhand AZ Pronto mount and tripod with slow motions and added tube rings.  This makes a lot of difference, and it's a nice little package now!

Edited July 10, 2023 by Second Time Around

[DaveL59]

I was thinking about rings for it also but never quite got around to that. I do kinda miss not having it here now too, so easy to just pop it out in the garden for a quick look when clouds permit vs the setting up of the bigger scopes. Was almost tempted to get one of the DX fracs but resisted the temptation so far, I'd like a mount with slo-mo controls if I was going to get another, but then I DIY'd a phone carrier that I can use on any of mine and they really should get more use than they have been.

[paulastro]

Welcome to the Starsense Club Stu, about time 😊. Thank you for your excellent report. I'll look forward to reading about how you get on using the SS unit on your Dob.  Having had my Starsense Dob   a year yesterday, I feel confident I already know the answer.  You're in for a real treat.

The first time I used it I said it was a game changer, and a year on I'm I'm still of the same mind.  It has delivered the best,most enjoyable and productive years observing I can recall. 

I also now have a second SS holder and base on a Vixen adapter which enables me to also use SS with my Altair 80ED, C5, and 130PDS.

I agree re the tripod and mounts being the achilles heel on the cheaper range, and I wasnt terribly impressed on a used DX version which I ended up returning.  In my view, FLOs reducing the price of the 8 inch Dob version to only £549 make it great value compared to the DX versions, and also compared to other brands Dobs without SS.

 

[Stu]

Thanks all for the responses, wasn’t expecting my little write up to get so much attention 🙏.

I will try to find some rings to the scope and I’m sure it will perform very well on a more solid mount. I think the OTA is just over 90mm from a quite measure but will check and see if I can find any.

@paulastro where did you get the second base from? That could be very handy 👍

[happy-kat]

It reads like starsense gives a faster start to a goto observing experience by pushto target involvement from the user, sounds like potentially a lot more engaging and successful

[Stu1smartcookie]

A nice review @Stu. This little device has been one of the most innovative and welcome additions to astronomy imo . 

No More frustration in locating targets . Positioned on my SkyTee it seldom needs re-alingning . 

 

[paulastro]

3 hours ago, Stu said:

Thanks all for the responses, wasn’t expecting my little write up to get so much attention 🙏.

I will try to find some rings to the scope and I’m sure it will perform very well on a more solid mount. I think the OTA is just over 90mm from a quite measure but will check and see if I can find any.

@paulastro where did you get the second base from? That could be very handy 👍

Stu.  Some months ago someone advertised a SS phone holder and base along with the remaining code numbers  They had bought one of the cheaper scopes to used the holder with their dob.  They had sold the dob and then had no use for it.

If I recall correctly  the ad was in 'the other place'.  I wasn't actually looking for one at the time, and it's the only one I've ever seen for sale without its scope.

Someone else later provided me with a printed Vixen finder foot to SS base adapter which is is the icing on the case, as it means I can use the SS system with any scope with a Vixen finder foot of course which is fabulous.

I can't see Celestron selling just the phone holders with a code number any time soon unfortunately.

Edited July 11, 2023 by paulastro
Added pics.

[bosun21]

Regarding pointing accuracy I found that a good initial alignment of the SS unit with the scope is essential. Once roughly aligned I always use two fingers on the phone screen to zoom in on your alignment target. I have found this helps considerably. So far every target I have selected has been in the FOV of a 17.5mm Morpheus.

[Stu]

1 hour ago, paulastro said:

Stu.  Some months ago someone advertised a SS phone holder and base along with the remaining code numbers  They had bought one of the cheaper scopes to used the holder with their dob.  They had sold the dob and then had no use for it.

If I recall correctly  the ad was in 'the other place'.  I wasn't actually looking for one at the time, and it's the only one I've ever seen for sale without its scope.

Someone else later provided me with a printed Vixen finder foot to SS base adapter which is is the icing on the case, as it means I can use the SS system with any scope with a Vixen finder foot of course which is fabulous.

I can't see Celestron selling just the phone holders with a code number any time soon unfortunately.

Looks good Paul! No doubt people could 3D print a holder with the finder show built into it, that would be the ultimate I guess?

My Tak finder base is mounted vertically so ideally I need to find a way of mounting to it so the SS remains upright, I’ll dig into my spares box!

[Second Time Around]

Here's a link to what you need to 3D print an adapter to fit on to  a standard Synta finder shoe:  https://www.thingiverse.com/thing:4868065

[Stu]

21 minutes ago, Second Time Around said:

Here's a link to what you need to 3D print an adapter to fit on to  a standard Synta finder shoe:  https://www.thingiverse.com/thing:4868065

That’s great, thank you. Would be good to print the SS holder on top of that adaptor so you didn’t need to source spare holders, is that possible?

[paulastro]

1 hour ago, Stu said:

Looks good Paul! No doubt people could 3D print a holder with the finder show built into it, that would be the ultimate I guess?

My Tak finder base is mounted vertically so ideally I need to find a way of mounting to it so the SS remains upright, I’ll dig into my spares box!

I use one of the multi-head finder holders I bought off a friend for this purpose - you can see it in the pics.

[Ratlet]

10 minutes ago, Stu said:

That’s great, thank you. Would be good to print the SS holder on top of that adaptor so you didn’t need to source spare holders, is that possible?

Do you mean the actual Starsense mount (the bit that hold the phone?)  That would be an interesting wee project.  You'd need to source a suitable mirror for it but would in theory be possible.

I'm sure I saw someone using a mirror diagonal for something similar. 

Edited July 11, 2023 by Ratlet

[paulastro]

2 hours ago, Stu1smartcookie said:

A nice review @Stu. This little device has been one of the most innovative and welcome additions to astronomy imo . 

No More frustration in locating targets . Positioned on my SkyTee it seldom needs re-alingning . 

 

I whole heartedly agree with you.  I'm amazed everyone doesn't use it by now.  It' really is game changing.

[bosun21]

7 minutes ago, paulastro said:

I use one of the multi-head finder holders I bought off a friend for this purpose - you can see it in the pics.

That’s exactly what I used for my SS. I just moved my optical finder to the side 

[bosun21]

7 minutes ago, Ratlet said:

Do you mean the actual Starsense mount (the bit that hold the phone?)  That would be an interesting wee project.  You'd need to source a suitable mirror for it but would in theory be possible.

I'm sure I saw someone using a mirror diagonal for something similar. 

The only drawback of this is that unless you build in a phone adjustment mechanism otherwise you will have to use that phone for ever.(no upgrades). Phone lens placement changes as well as dimensions in different models and makes.

[Stu]

40 minutes ago, Ratlet said:

Do you mean the actual Starsense mount (the bit that hold the phone?)  That would be an interesting wee project.  You'd need to source a suitable mirror for it but would in theory be possible.

I'm sure I saw someone using a mirror diagonal for something similar. 

I’ve seen some DIY versions of the whole thing, but actually I was just thinking of the base part that the SS fits into. If you had 3D printed versions of those it would be handy I think.

[StevieDvd]

I've printed a couple of  adapters for the SS - designed via Tinkercad which can be a bit of a pain to get dimensions accurate, but it's free and fairly easy to use.

This has 2 bolt connections (one in front shown and similar at the back) so you can bolt it to a dovetail or an adapter of your own.  I used m4 brass threaded inserts & m4 bolts for the side bolts though it's a tight fit without them. STL file below

SS_Adapterv1.stl

 

The above was an adapter to raise the existing base.  Made in 3 parts. The filler part was to use the existing base and allow you to connect parts to it, similar to a dovetail with a through slot for bolts. The middle part was an existing metal part I had that bolts to the first part. And then the finder shoe dovetail that screws into the metal middle column. Made for a 70mm scope adapter - not sure if the bigger scopes have a different curvature.

STL file below

StarSenseFillerV2.stl

Those with a 3d slicer program or designer that can import the STL can see the 3d view of the parts better.

Feel free to use/modify as you desire.

 

StarSenseBase.stl  this is a new untried plate I knocked up using the same design of a slotted fitment so a dovetail or findershoe can be fitted to the Celestron SS holder.  Have yet to print it and do a test fit myself as I have to get my printer base level & auto-level sorted properly.

 

[RobertI]

FWIW, I have used cable ties to attach the SS mount to the tube. Not such a good solution if you want to move the unit between scopes, but it works fine, is secure, and can be mounted anywhere on the tube, space permitting. One of those temporary solutions that will probably be in place for years! 😆

[DaveL59]

3 hours ago, bosun21 said:

The only drawback of this is that unless you build in a phone adjustment mechanism otherwise you will have to use that phone for ever.(no upgrades). Phone lens placement changes as well as dimensions in different models and makes.

Agreed on that. I custom made a carrier for my Samsung Note 10+ from Delron sheet and used a prism to reflect the sky into the camera, works well. Our lost friend Johninderby did his with a cut down cheap diagonal for the reflective surface, there's a thread here somewhere where we did all that a couple years back. I know @markse68 3D printed a custom carrier for his phone so we all went slightly different routes. I no longer have the scope here as its now with my daughter but can still use my current phone, I'd have to make a new carrier if I do change phones but since I tend to use the same one for a few years, not so big a deal for me, daughter has the exact same model so a nice simple switch around if we ever need to 🙂 

I guess another possibility would be to adapt a NeXYZ carrier and fit a mirror/prism under it, given the starsense holder is the same mechanism  minus the eyepiece clamp.

[Ratlet]

I'm working long shifts so not had a chance to play with mine yesterday.  I removed the arm and put the scope in some spare tube rings I've got kicking about.  Fit nicely between the gubbins.  On the carbon fibre tripod the whole setup is incredibly light.  Think this will be excellent for showing of planet/moon to folk.

Really only looking to align the red dot as I'm wanting to see how this handles Jupiter.

I must admit that the chromatic aberration is not bad at all in daylight.  I'm not sure what I was expecting but it's better than the svbony binos I got which are apparently ed coated.  It's also really sharp.

The focuser leaves a lot to be desired, but I'm not sure if an upgrade would be possible without spending silly money.

Very excited to give this a try under dark skies.