Unboxing - Celestron Travelscope 70

[SnakeyJ]

OK - so this is a small box, for not very much money - £ 49.99 delivered! http://www.amazon.co.uk/Celestron-21035-Travel-Scope-Telescope/dp/B001TI9Y2M

Not that I'm planning on taking this hiking, or twitching - I'm purely after a guidescope and at 400mm focal length and F5.7, this appeared excellent value and a fair bit lighter than the standard Skywatcher ST80.

What's in the box?

OTA - weighing less than 750gms, but definitely in need of longer dewshield. Focuser is a little sloppy when fully extended beyond 2/3 of 70mm, though this is resolved by tightening the locknut 1.25" adaptor has female T thread to focus tube and male T thread to EP. Comes bolted to 2" of standard dovetail bar with 2 threaded 1/4-20 holes.

The Objective shows the expected coating, and the internal OTA and focuser tube are painted in almost matt black. And I think there's a single baffle 2/3 of the way down the OTA:

Diagonal - cheap and not so cheerful 1.25" 45deg corrected image, can't really fault this at the price.

2 x Celestron EPs 10mm and 20mm, probably MA or Kelner, steel rather than the plastic sleeved ones which I have previously seen with the Astronmaster. Probably not so good, but come in nice reusable plastic cases.

Finderscope 5 x 24 - difficult to avoid the more purile anologies, so lets play it safe with chocolate fireguard

And then there's that tripod - and yes it does shake more than the King of Rock'n Roll, but c'mon everybody it works and at low mag on a still night is undoubtedly better than nothing and hey I'll probably use it for my compact camera!

A backpack/carry case - suspect the stitching will probably part and the zips give way with any serious use, but it is padded and offers some protection.

And last but not least, don't forget the Sky X – First Light Edition CD-ROM is also included with this product. A computerized sky map that features a 10,000 object database, 75 color images, horizontal projection, custom sky chart printing, and zoom capability. A fun, useful and educational product. According to the box this retails for 69USD (more than I paid for the whole delivered package - whoopee!).

OK - I'm getting a little flippant and I'm actually quite impressed with the whole package given the incredibly low price and I will have to give it a proper look through when time and conditions allow.

All rather moot though, I really only want it as a guide scope and with greater aperture, lower price than a 10x50 finder guider and not a lot more weight I reckon it will be well up to the job - even with a low end webcam or my firefly to start with. I will need to sort out the mounting, but rather than guide rings, I think I can bolt this down on top of a standard SW dovetail bar that I already have as a stiffener for my tube rings. I'm pretty sure the FOV (38.78' x 24.75' with the small firefly chip should) give me something on axis, though tube rings and probably a 50mm T thread extension tube may be required in the not too distant. I'll post another thread on it's performance as a guide scope as soon as I get some hands on.

[baggywrinkle]

Nice report. As you say for the price it is decent value, especially if it makes it as a guide scope.

[Daddystu]

It is a very good guidescope. I often have a choice of 20+ stars to guide on in my FOV with the QHY5 and its 1/2" chip. I have it in guidescope rings but I've not had to adjust to find a star as of yet. The dew shield is a little short. I'm sure I have an elastic band and some plastic sheeting around here somewhere.

[SnakeyJ]

It is a very good guidescope. I often have a choice of 20+ stars to guide on in my FOV with the QHY5 and its 1/2" chip. I have it in guidescope rings but I've not had to adjust to find a star as of yet. The dew shield is a little short. I'm sure I have an elastic band and some plastic sheeting around here somewhere.

Thanks DaddyStu - exactly what I wanted to hear!

I've just hit a snag with stacking the 2 bits of Synta Dovetail - I naively assumed that the profile would stack nicely and it's not even close. I will have to put a little strip of aluminium plate in between to give a flat surface, so 10 minutes unanticipated work to follow and hopefully I can still get out and give it a try tonight providing I can get the nippers off to bed early.

Jake

[JamesF]

I've had thoughts about using one of these as a finder/finder-guider for my longer focal length scopes. Would you mind measuring the length of the tube from the objective to the back end of the focuser body? It would be handy to know how far the draw tube is likely to stick out with a camera in it.

James

[SnakeyJ]

James,

Certainly - Fully extended I have exactly 398mm from the front of the dew shield to the rear of the T thread on the eyepiece adaptor. Focuser travel is 70mm, so retracted you would be @ 328mm. Celestron's published focal length is 400mm, so it may need a little extension if using without the diagonal, though a T extension tube would screw in as a replacement to the EP Adaptor. DaddyStu is better placed to comment before I get this mounted and running.

Jake

[JamesF]

Does sound a bit like an extension might be required given the 400mm focal length. It could end up longer than the telescope it's guiding

James

[SnakeyJ]

Does sound a bit like an extension might be required given the 400mm focal length. It could end up longer than the telescope it's guiding

James

James,

Just discovered how to remove the dew shield (push fit) from the rear of the objective to the rear of the T thread on the eyepiece adaptor I make 360mm, so you're really looking for another 50mm/2" extension tube to make things comfortable.

Jake

[JamesF]

Just discovered how to remove the dew shield (push fit) from the rear of the objective to the rear of the T thread on the eyepiece adaptor I make 360mm, so you're really looking for another 50mm/2" extension tube to make things comfortable.

It would be half-tempting to replace the tube entirely with one long enough that the focuser was close to the inwards limit of its travel

James

[SnakeyJ]

In my OP, I have incorrectly stated that the thread on the end of the steel focus tube is standard T thread - apologies for the duff info, but it is actually a slightly smaller diameter and coarser thread (I don't have the means to accurately measure at the moment).

However, I have managed to fit a straight extension tube, which is the body tube from a Meade basic camera adaptor. This is female to male T threaded and fits to the T thread on the supplied 1.25" adaptor. At the other end I've fitted a TS low profile 1.25" compression adaptor. The whole combination is a probably 100gms heavier than it needs to be, but I had all these bits to hand and the end result is reassuringly solid.

Now I just need to find a sufficiently sensitive guide cam to complete the rig:

I have a couple of cheap webcams; XBox Live, MS Lifecam HD-3000 - these work with PHD as WDM cameras, but are probably not sensitive enough. I have the infamouse TS Planetary Imager - the drivers for this are rubbish and hang PHD after selection (shame as the Sony HAD CCD would have been nice and sensitive). I also have the Pt Grey Firefly MV Mono - this will probably work with PHD using the ascom driver developed by Ludovic Pollet, http://pludov.free.f...om_firefly.html, though it has a max exposure of just under 1 sec - might just work with the 70mm guide scope, but will rather limit the choice of stars!

I think I'll go with the Pt Grey and keep an eye out for a s/h mono guide cam!

[SnakeyJ]

I have had to shorten the extension tubes, but now have this working and achieving focus with Point Grey Firefly. However, I'm having some issues with Ludovic Pollet's ascom driver in PHD. His version does work and will capture/loop, but the controls for the camera are not accessible due, I think to the more recent version of Flycapture SDK. I think he wrote the driver around 2.3.3.18 and the current version is 2.5.3.4. Unfortunately Pt Grey do not provide the old version for download, so I'm on the look if anyone has Flycap2 x86 2.3.3.18.

Otherwise Ludovic does provide the source code, so it may be possible to hack/fork this for the newer versions.

[SnakeyJ]

For completeness, here's the system error messages; within PHD (Ascom Chooser), Though the second dialogue confirms connection. The final is from Ascom Diagnostics:

The full details from this last error are as follows:

See the end of this message for details on invoking

just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************

System.IO.FileNotFoundException: Could not load file or assembly 'FlyCapture2GUI_Managed_v100, Version=0.0.0.0, Culture=neutral, PublicKeyToken=74143acea6c06080' or one of its dependencies. The system cannot find the file specified.

at Microsoft.VisualBasic.CompilerServices.LateBinding.InternalLateCall(Object o, Type objType, String name, Object[] args, String[] paramnames, Boolean[] CopyBack, Boolean IgnoreReturn)

at Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateCall(Object Instance, Type Type, String MemberName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack, Boolean IgnoreReturn)

at ASCOM.Utilities.ConnectForm.btnProperties_Click(Object sender, EventArgs e) in C:\ASCOM Build\Export\ASCOM.Utilities\ASCOM Diagnostics\ConnectForm.vb:line 150

at System.Windows.Forms.Control.onclick(EventArgs e)

at System.Windows.Forms.Button.onmouseup(MouseEventArgs mevent)

at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)

at System.Windows.Forms.Control.WndProc(Message& m)

at System.Windows.Forms.ButtonBase.WndProc(Message& m)

at System.Windows.Forms.Button.WndProc(Message& m)

at System.Windows.Forms.Control.ControlNativewindow.WndProc(Message& m)

at System.Windows.Forms.Nativewindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

************** Loaded Assemblies **************

mscorlib

Assembly Version: 2.0.0.0

Win32 Version: 2.0.50727.5472 (Win7SP1GDR.050727-5400)

CodeBase: file:///C:/Windows/Microsoft.NET/Framework64/v2.0.50727/mscorlib.dll

----------------------------------------

ASCOM Diagnostics

Assembly Version: 6.0.0.0

Win32 Version: 6.0.21573.2300

CodeBase: file:///C:/Program%20Files%20(x86)/ASCOM/Platform%206/Tools/ASCOM%20Diagnostics.exe

----------------------------------------

Microsoft.VisualBasic

Assembly Version: 8.0.0.0

Win32 Version: 8.0.50727.5420 (Win7SP1.050727-5400)

CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Microsoft.VisualBasic/8.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualBasic.dll

----------------------------------------

System

Assembly Version: 2.0.0.0

Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400)

CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll

----------------------------------------

System.Windows.Forms

Assembly Version: 2.0.0.0

Win32 Version: 2.0.50727.5468 (Win7SP1GDR.050727-5400)

CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll

----------------------------------------

System.Drawing

Assembly Version: 2.0.0.0

Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400)

CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll

----------------------------------------

System.Runtime.Remoting

Assembly Version: 2.0.0.0

Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)

CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Runtime.Remoting/2.0.0.0__b77a5c561934e089/System.Runtime.Remoting.dll

----------------------------------------

System.Configuration

Assembly Version: 2.0.0.0

Win32 Version: 2.0.50727.5476 (Win7SP1GDR.050727-5400)

CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Configuration/2.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll

----------------------------------------

System.Xml

Assembly Version: 2.0.0.0

Win32 Version: 2.0.50727.5476 (Win7SP1GDR.050727-5400)

CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll

----------------------------------------

ASCOM.Utilities

Assembly Version: 6.0.0.0

Win32 Version: 6.0.21573.2300

CodeBase: file:///C:/Windows/assembly/GAC_MSIL/ASCOM.Utilities/6.0.0.0__565de7938946fba7/ASCOM.Utilities.dll

----------------------------------------

System.Core

Assembly Version: 3.5.0.0

[JamesF]

Best I can do is 2.3.3.19, which is what I happened to have already downloaded when I was tinkering with this. I had problems with it, but that may be down to running on a 64-bit machine. You're welcome to a copy if you think it's worth a go though.

I've opened a support case with Point Grey to see if it's possible to get a copy of 2.3.3.18.

James

[JamesF]

For completeness, here's the system error messages; within PHD (Ascom Chooser), Though the second dialogue confirms connection.

Ah, that's exactly the problem I was having. Is your system 64-bit or 32-bit?

James

[SnakeyJ]

James,

I'm not alone - always reassuring. I also have the 2.3.3.19 version in x86 and x64, but nothing predating this.

I did find some interesting threads discussing a very similar issue with this - thank goodness for Google Translate, which does a fair job. Though I have tried copying the dlls around and it still doesn't cure this.

http://91.121.211.202/~webastro/forum/showthread.php?p=1544662&langid=1

http://www.webastro.net/forum/showthread.php?p=1467989

Ludovic does say it should work on Win7 x64, using the x86 SDK and the posts in these forums look like it did (at least on this earlier version of Flycap2).

Perhaps I can manage without, but the option to stack multiple frames to achieve longer integration times looks very useful increasing the sensitivity and improve the snr.

[SnakeyJ]

Thanks James for contacting Pt Grey support and getting access to the 2.3.3.18 version of Flycap2.

This now works - though initially although ascom was able to launch the Flycap2 camera selection dialogue, it was hanging with numbers out of range when I tried to select and configure the camera. This was resolved by going in to device manager and changing the driver to the earliest listed within the Flycap2/SDK folder. I then could not get anything at all out of the camera, and after checking all the settings decided to find the moon - and failed! After some cussing and going around in circles I removed the camera from the guide scope and sure enough discovered that I couldn't see anything at all through the ota. A quick check with a torch revealed that the barlow I was using as an extension tube had a plug inserted in it.

Surprisingly, it was considerably easier to get this running after this point!

I've found that the dark frame is essential and there is still something going on with auto exposure/white balance that I need to find and turn off - however around M27, I am picking up 6 decent candidate stars in the fov and despite some occassional low SNR warnings this seems to have locked on, calibrated and is guiding successfully. Although the moon is very bright and I do not expect anything great back, I am currently guiding and doing 60sec exposures on M27 with red filter and gain at 10% (101) - the first few frames looked pretty decent in preview with no obvious star trails, but I'll let it run on for 40 frames and log the guiding data for some PECprep data.

If I can resolve the AE/WB issue this camera looks like it will do the business, at least mounted on the travelscope 70.

Not expecting much back from the sessions imaging, but I will post a picture and a tally of how many subs were successful (assuming no imminent cloud spoils the view).

[SnakeyJ]

Not sure what all this means - but here are the stats from PECprep:

Capture Declination: 0.00 deg

Capture Resolution: 0.49 asec/px

Worm Period: 213 Secs

Steps/Period: 22293

Sample Count: 487

Sample Int.: 1.00 Secs

Trend: Y = 0.0005X + -0.1

Peak PE+: 0.27 arcsecs

Peak PE-: -0.30 arcsecs

RMS PE: 0.13 arcsecs

MaxRate: 0.02 arcsec/S

MaxRate: 0.00 x sidereal

Av. PE+: 0.11 arcsecs

Av. PE-: -0.09 arcsecs

Max Delta+: 0.21 arcsecs

Max Delta-: -0.24 arcsecs

I still ended up with a lot of trailing on the subs - though I think the guiding cut out quite early on due to bright moon and low SNR

[Cath]

Good to see their is a good use for the little firefly's

Well done Jake.

"White balance" with a monochrome camera - doesn't sound right?

[SnakeyJ]

"White balance" with a monochrome camera - doesn't sound right?

Not sure on the terminology on this, but it was some kind of autoexposure/balance, which was intermittantly increasing the image brightness. It made focusing a little strange, as I was trying to view the capture windown on my laptop screen from 2-3m distance. I had the PHD brightness slider set to the minimum, but at times I was still seeing an almost white image. However, It didn't appear to affect the tracking/lock that PHD had on a star.

It was a very bright full moon last night, and I was looking at M27 for my guided run which was looking 20-30 degrees off the moon. I might be able to improve contrast here by extending the dew shield on this scope and perhaps some flocking. Something else to play with next time it clouds over

[oymd]

looks like a nice little scope...!!

[Dark Knight Gazer]

I'm a bit late to the party here, but...

How have you attached the 70mm to the main scope?  It doesn't come with tube rings and they are seeming impossible to find on the internet!  I am thinking of mounting it on a Skywatcher ED80.  I have a dovetail mounting bar.

Thanks,

DKG

[SnakeyJ]

I'm a bit late to the party here, but...

How have you attached the 70mm to the main scope? It doesn't come with tube rings and they are seeming impossible to find on the internet! I am thinking of mounting it on a Skywatcher ED80. I have a dovetail mounting bar.

Thanks,

DKG

I had a second dovetail on top of the tube rings for my 200P. I drilled through and bolted to the small dovetail on the travelmate, with a small strip of aluminium plate between. It worked very well and I never had an issue finding a guide star despite having no off axis movement.