Cosmic Geoff

You would need a second dovetail bar and some tube rings. I think you are under-estimating the weight of the 500x102mm (I have one). 

If I were you, I would provide the solar scope with its own mount.  A CPC800 is heavy - I have one and it takes me half an hour to heave it out of its storage, attach the fragile bits and get it ready for observing.  If you give the solar scope its own mount you could deploy it far quicker.

If you carry out your scheme, be sure not to uncap the CPC800 OTA or its finder while solar observing, otherwise you will melt something.

I'm not familiar with the mount, but you can probably use it as a manual just by leaving the clutches slackened off.  It may also be possible to reconfigure it as an alt-az if you reconfigure it for 0 deg or 90 deg latitude.

Personally I don't believe in this 'learn the sky' philosophy much.  This isn't the 19th century. Electronics rule.

Just to add my few words of advice. Don't get hung up on the chromatic aberration in achromatic scopes.  Many people were perfectly happy with their long focal ratio achromatic refractors before the ED and APO scopes were introduced.  Also note that visible chromatic aberration does not = Ruins Your Evening.  Even with the f5 achromats, the chromatic aberration, while definitely present, is more obvious on some targets (e.g. the edge of the Moon) than on others (e.g galaxies and nebulae)

I have a classic brass 70mm refractor with a very long focal ratio which shows no chromatic aberration at all.

Beware of budget telescopes that are 'too cheap'.  At one point I bought a supermarket refractor which, while in most respects excellent value, had an objective lens which (as I eventually realised) was not good enough. I might have tried sourcing an upgrade, but there was no way of getting the objective lens off without using a saw. 

At one point I had both a narrow-field (f12.5) and a wide-field telescope  in the 4" & 5" aperture range. I used the narrow-field instrument far more, and made little use of the 102mm f5 achromat till I discovered I could image with it.

The Startravel 102mm f5 achromat appears to be a short version of Sky-watcher's Evostar, and for the price is a well-made instrument with the focuser, dew-shield, tube etc all made of metal.  It makes a useful budget imaging scope but is not much good for viewing fine detail on planets etc.

I'm not familiar with the scope and mount, but suspect the mount drive is purely intended to ease visual observing.  If you read up on what people use for serious astro imaging, you will see the difference...

There are various things you can check in the daylight before binning the mount, e.g. has anything happened to jam the movement? Is the azimuth motor actually running? Are there any fault messages on the handset? Will moving the connectors clear a bad connection?

(Note that the altitude and azimuth motor/gear units appear identical and could be swapped over as a test.)

Most of the small GoTo mounts you can buy separately come from Skywatcher, and having used a Nexstar you may not like the Synscan operating system much. 🙄

If you do buy another mount, beware the effect of not having the support on the same side of the scope as with the SLT.

12 minutes ago, iwols said:

thanks they were that bad didnt bother capturing it could just make the two bands out just

The raw image always looks bad on screen.  If you can make out any detail it often means it's a good night.

No idea how bad your result was.  ASI462MC and C8 works well for me.

If you are trying for the best result, you need an ADC even at moderate altitudes, as the dispersion is significant compared with the fine detail you are trying to resolve.

And yes, the ADC has the same effect on stars.

Moon - irrelevant.

I'm not sure exactly what bit you are trying to unscrew, but if it's made of aluminium etc then heating it with a hot air gun should expand the ring and enable it to be unscrewed.  Don't heat up the focuser knob.

Anyone considering remote planetary imaging should first do some planetary imaging at the scope and then think about how they will perform the various operations remotely.  Getting the planet on the camera chip, in focus, and reducing the region-of-interest (ROI) can be tricky enough at the scope without trying to do it remotely.  I have yet to see a remotely-adjustable ADC. 😁  If you are going to do these setup operations at the scope it hardly seems worth the bother of going indoors to do the actual capture.

On 14/09/2022 at 16:53, catburglar said:

1. Simple Tracking…you may not need or want GoTo, but could you get an equatorial platform for your dob?

Nic - I have no experience of these equatorial platforms, but it occurs to me that getting one might solve a lot of your problems.  For planetary imaging it only needs to work with the scope pointed S/SE/SW at the ecliptic. And it might prove useful for visual observing too. 

18 minutes ago, SzabiB said:

I think my tube is over 7kg

I seriously doubt that a 114mm Newtonian can weigh that much.  Perhaps the figure you have seen is the overall package weight. For reference, my much bigger 203mm Newtonian was about 10 Kg.  

3 minutes ago, Astro_Nic said:

Now you've got me worried I'll spend all of this and not be able to focus and it will all be a waste!  Is there a way to find out prior to I spend a small fortune?

I'm not sure. You could buy a cheap, nasty astro camera on ebay and see if it comes into focus. If it doesn't, you will have only wasted £10 or so.

These topics have mostly been extensively aired on this forum. Just read the previous posts.

The choice of alternative and less wobbly mounts for your scope is huge. The choice at £200 is rather more limited...

The Baader Skysurfer III is a good red-dot finder which IIRC comes with a collection of alternative mounting parts for fixing it to a scope.

You need an ADC for good results, but you may find difficulty in getting it to work with a Newtonian.  You might also have trouble getting the camera to focus with a Newtonian not built for imaging, but a barlow might help here. 

80GB sounds a lot. If that's correct, how long do you think it will take your equipment to move this amount of data around, and to process it?

A gentle reminder that getting the right astro kit for the job, (e.g. a GoTo SCT) will enable you to:

1) let the hardware take care of tracking

2) let you hang any kit on the scope without worrying whether you will run out of focus travel

3) Allow you to get the planet on chip without too much trouble, potentially reducing chip size and camera cost.

4) Reduce data storage requirements and hence laptop cost.

5) Reduce size of video files to be processed

6) If you can't crop the videos after recording, recording with a small ROI will make it practical to archive your videos and re-process them months or years later.

7) Reduce time and labour required.

2 hours ago, Astro_Nic said:

but a lot of people have suggested the 585 to help keep the target on the sensor more easily. 

That should work, but try to find out what amount of data 5000 full-size frames represents with this camera, and what the maximum frame rate would be., before you invest £400 in it.  (With an ASI 224 or ASI462, 5000 frames of 320x240 px = about 350MB, and frame rate is about 250 frames/sec with short exposures of a few ms on bright planets). 

Hard to advise. As you note, a Dob is not ideal for the purpose.  I am currently using an ASI462MC, which is an improvement on the ASI224MC in that the former has smaller pixels, tending to capture more planetary detail.  The ASI462 has a small rectangular sensor, and in use I crop the region-of-interest down to 320x240 pixels, which with my SCT means that Jupiter fills most of the cropped frame(!).  This minimises the amount of data and storage wasted capturing a lot of black sky.  I imagine this would be impossible without a good, powered mount, and you will at least need to use a much larger ROI.

With the focal length of your scope you will need to use either a small-pixel camera (e.g. 2.9um) or a Barlow lens to get adequate image scale.

Getting the planet image on the (full) chip, centering, switching to desired ROI and fine focusing will all be more difficult without a driven mount.

There is an imager who has posted some fine images in 'Planetary Imaging' using a Dob.

Your 14" will be (even) more affected by bad seeing than my 8".

8 hours ago, roger jerome said:

Great images……. How many fps will the asi462mc do?

I am getting around 250fps on brighter planets with a USB3 equipped laptop.  Check the online spec for details. 

The rate achieved depends on the exposure time and other factors.

It's not bad, but a C9.25 should be capable of more under the right conditions.  If you tell us what capture program you were using (Sharpcap?) and copy the camera setting file here we might have some tips.

The image looks like the focus could be better.  With Jupiter you can use the moons as focusing aids.

Got Jupiter and Saturn in late evening, and Mars after midnight. Some of my best images so far with this new camera.  ASI462MC, CPC800, typically 5000 frames, best 30%, processed in Autostakkert (for Jupiter), Registax 6.  Seeing seemed good after midnight and I could easily see detail on laptop screen.

The moon in Jupiter image is Io. Mars image shows Syrtis Major and Hellas (brighter region).

6 hours ago, RobertI said:

My personal experience with my C8 is that bright stars are not always pinpoint and can seem a bit ‘hairy’ (

Sounds like my CPC800 before I tweaked the collimation.  My C8 SE did not produce 'hairy' stars.  

I have often seen reports that SCT views are 'mushy' with the implication that these instruments are inferior to other designs.  Following a recent experience I now suspect that the issue could be poor collimation. I have two SCTs - a C8 SE (quick deploy) and a CPC800 (for serious business).

I had a feeling that the C8 SE imaged better, yet the CPC800 resolved double stars OK.  The views through the C8 SE always looked perfectly fine, with suitably positioned stars showing an Airy disc and rings. But was the view of doubles through the CPC800 always a little untidy?  

Eventually, I carried out a side-by-side trial, swapping over the diagonals and eyepieces to eliminate these as a possible cause of trouble. Result: the C8 SE was definitely performing better.  The only possible conclusion: either the CPC800 was a 'Friday Afternoon' job or the collimation was slightly out.  So I aimed it at Polaris and slackened one of the secondary aligning screws by a fraction of a turn. Ugh, worse.  I slackened an opposing screw slightly and that definitely improved matters. So left it like that, and tried some planetary imaging with it within hours.  Result - significantly better than before, and pretty much like the kind of result I sometimes got from the C8 on the less stable SE mount.

So, a very slight mis-collimation of a SCT significantly affects the performance.

I have never tried saving and re-using a Registax scheme, (though I have used it hundreds of times) so don't worry about it.

It would help if you told us which capture program you are using.

I have dug up some of my results for 2018. Here is the actual log for one of the images: (below) Nowadays I would expect to find some more colour. Getting a sharp but realistic-looking image is something of an art.

You will note that the exposure is only 3 ms.  The capture area is 480x480 pixels. Nowadays with a better mount I usually use 320x240px.

The gain is set at 100. Whether I was happy with 100 or there was no way of altering it, I don't recall.  The size of the .ser file was 228MB (probably 3000 frames).  The .ser file was processed in Registax 6. (Lately I have begun using Autostakkert + Registax). 

[ZWO ASI120MC]
Debayer Preview=On
Pan=400
Tilt=240
Output Format=SER file (*.ser)
Binning=1
Capture Area=480x480
Colour Space=RAW8
Temperature=17.7
Discard Split Frames=Off
High Speed Mode=Off
Turbo USB=80(Auto)
Flip=None
Frame Rate Limit=Maximum
Gain=100
Exposure=0.003079
Timestamp Frames=Off
White Bal (B)=100
White Bal (R)=56
Brightness=8
Auto Exp Max Gain=50
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Mono Bin=Off
Apply Flat=None
Subtract Dark=None
#Black Point
Display Black Point=0
#MidTone Point
Display MidTone Point=0.5
#White Point
Display White Point=1
TimeStamp=2018-06-24T23:11:01.0156882Z
SharpCapVersion=3.1.5049.0

And here is the corresponding image:  

What capture program are you using? In Sharpcap 4 there is no problem in turning up the gain from 100 to 350 or so.  I did exactly that when I was using my ASI120MC with Sharpcap 3.  

I have a C8 SE (same mount as the OP).  Getting it to align should be straightforward provided you enter all the settings correctly.  Check the location and time/date and time zone and ensure they are all correct and in the correct format.   If once 'set up' it offers you a planet that you know is below the horizon (or vice versa), that is a clue that the settings are wrong.  Yes, I know this can be frustrating if you have never done it before.

If you can't make it behave with the handset, plugging in wifi gadgets will not help, unless you strike lucky and plug in something that automatically finds and enters the position, time, etc.

One thing to watch out for is bad connection of the power plug, exacerbated as the mount swings around while the power source stays put.