Cosmic Geoff

1 hour ago, uhb1966 said:

Connector is a simple 5,5mm outside/2.1mm inside jack.

These connectors are a regular cause of problems on various mounts. Two tips: expand the split centre contact slightly with a craft knife to give firmer contact. Use a cable tie or similar to restrain the cable near the connector. 

One can't help comparing this with the update procedure for the Seestar S50 device and its smartphone app.  In the latter a few pokes of the finger do the job - no cables, no special app installations etc etc.  Celestron and other astro equipment manufacturers need to join the 21st century.

Some months ago I updated the firmware on a Celestron C8 SE for my local astro club. It was a right pain, even though I had done firmware updates before.

I realised an odd thing when I reassembled my C8 with its hardware Starsense Autoalign system in Buckinghamshire after a trip to a dark skies site in Shropshire. I had forgotten about changing the location till I took it outside here. But it performed perfectly in Shropshire, placing every object I wanted to view within the field of a 25mm eyepiece.

Is the ability to save separate FITS files (rather than stacked) available in the generally distributed software upgrades, or is is only available in beta versions distributed to beta testers? Various beta testers have published Youtube videos indicating that they had this feature available to them.

This is from the ZWO Seestar site dated July: " Moreover, our Pro Mode, coming soon, will introduce exciting additional features, including the ability to save individual images from each exposure for users to further enhance and personalize."

So far as I know, the 'Pro Mode' remains vapourware.

44 minutes ago, M40 said:

Errrm not at all last night 🤣 time limitations being what it was, I just went for it.

Likewise.  Once used on the sky and focused, it seems to hold focus.

43 minutes ago, M40 said:

I had a go at something different tonight, Epsilon Lyrae, the double double

How did you get it to aim at that? And name it? I could still make use of a decent manual for this device. 

How does one get it to save a set of FITS files rather than a stacked FITS file?

Why can I select NGC147 but not NGC185?

A month after my first light with the S50 at a dark skies site in Shropshire, I got a clear night at home and was able to see what the S50, now with the latest software, V1.9 and v1.58, would do in Bortle 6 skies.  

Some results are posted in the EEVA Reports part of the forum. I note that it now tags the smartphone .jpgs.

I imaged NGC 7293, the Helix Nebula, the biggest planetary nebula, and was pleased with the result, considering that when I tried for it with my other EEVA rig, it was a total fail. Likewise NGC 6995 (Veil), which looks much better than my effort with the other outfit.  Also IC5070, which I had not imaged previously.

The LP filter was engaged for all of these.  A couple of galaxies, also with the LP filter engaged, were disappointing, with hardly anything visible.

Three Seestar images taken 13 Oct 2023:

These are iphone images, reduced in size by 50%.  Bortle 6 skies,  v1.9 & v1.58

The background looks blacker in the originals.

You should be able to look up what the update actually does.   If the changes don't look relevant, it might be wise to leave well alone so long as the mount is working.

The Startravel at f5 is faster.  

You do not need an ASIAR, but if it's compatible I suppose you could use one instead of a laptop.

I use a laptop for EAA.

Why do you want to update the firmware?

I suggest reading what your user manual says about updating the firmware (if anything.)

You'd need a Barlow lens or equivalent to extend the focal length, and check the spec of your camera to see it you can get the high video frame rate and reduced ROI (region of interest) required for planetary imaging.  If not, you'll be looking at buying a dedicated planetary camera - various new models are available, some with 2.9um pixels. AFAIK, planetary imagers generally use a Windows laptop rather than an ASAIR to control the imaging.  You may also want an ADC (atmospheric dispersion corrector), a filter wheel, and a good-quality optical finder to help get the target on the camera chip.

You should be able to do solar imaging using a full-aperture solar filter, and some safe means of aiming the scope at the Sun.

An ADC is most useful when the planet is low on the sky, e.g. Saturn this month.  It is not clear why you should be getting a blue tint at both sides of the planet.   We assume you are imaging with Jupiter high in the sky.  Atmospheric dispersion typically gives red AND blue fringing.

If you want to do deep-sky imaging, you'd want the enhanced version with the ST-4 port, otherwise you'd be limited to short exposures.

If you just want to do planetary imaging, you could manage with the single-motor version as the exposure times will be short.  

I actually had the single-motor version on my EQ-5, and I found it awkward to have the RA slow-motion worked electrically, and the Dec slow-motion mechanical with the control in a different place.  It would probably have been more convenient to have both controls on one handset.

The detail is not bad for the size of scope.  I would suggest though that you get the cloud belts roughly horizontal, and that if you were using a diagonal that you de-flip the image accordingly.

You could use a smaller ROI to avoid pointlessly using file space to record a lot of black sky. 

Your color balance looks right in most of the images, except that some have a blue tint at the edges.

There should not be any problem getting the 'instant' .jpg files off your smartphone.  With an iphone, you can either connect to a PC via a Lightning to USB cable and 'allow', or set up icloud so that the phone images are made available on your PC without any further intervention from you.

I don't know about Android phones, but something similar ought to be available.

I found out the hard way that even if a SCT seems to work well on double stars, the collimation can still be slightly out, with a noticeable effect on planetary imaging quality.

17 minutes ago, davidc135 said:

spending over £2k

But see the forum's For Sale section...  £1400  for a C925. 

I have found that the 'seeing' is a major factor in planetary imaging performance.  So a 9.25" will give a slight improvement, and a 11" a more marked improvement in performance, but only if the seeing is good. If the seeing is bad, the bigger scope might actually perform worse. 

The central obstruction is not really an issue. The % loss of light isn't of significance, though the obstruction does cause some loss of contrast. But you can turn the contrast up during post-processing of images. 

The EDGE HD models have extra correcting lenses to give a flatter field for deep-sky imaging, but you don't need this feature for imaging a planet. On the other hand, the EDGE HD models are said to be finished to higher standards, allegedly giving a better optical performance.  If you are contemplating using a focal reducer at any time, note that the regular f6.3 FR is not too costly but the HD focal reducer is insanely expensive.

The OP does not mention what mount he is using. This has some bearing on how manageable the scope is.  I actually use a CPC800, which is close to being the ideal planetary imaging scope (for its size).  At nearly 20Kg I find the fork/OTA assembly as heavy as I'd want to handle, deterring me from buying a CPC925 or a C11.   If you have the SCT on a different mount, then each weight (OTA, mount. tripod, counterweight) to be handled is much less. 

Note that a fat OTA can be awkward to handle and mount up unless it has added grip-handles, e.g a second dovetail bar opposite the main one.  And the bigger it is, the more awkward it will be to handle.  People have dropped these OTAs! Usually with fatal results.

So in answer to the original question, buy what you like, but be aware of potential negatives.

Also note that used SCTs don't hold their price well (think 50% of the price of a new one) so you can save a wad of money buying used.

Here's a couple of Seestar images (phone .jpg) that I took on 15th Sept during its first outing.  IC5146 and NGC7023.  I have not managed another session with it since.  (clouds) These have not been processed at all except to up the contrast and rotate 90 deg to better fit projection screens.  The stack times were short as I was just trying to see what it would do on various objects.   It's impressive what it can do in a few minutes. A brilliant EEVA tool.

I have noticed that because of the way Seestar works, everybody's images of the popular objects have much the same framing.  🙂

I tried processing the FITS files from the Seestar, but could not improve on the instant jpg's.    Maybe post-processing works better with a longer series of stacked exposures.  Some testers have run over 1 hour on a single object. 

13 hours ago, powerlord said:

I mean, the whole S50 cost me 300 quid.

How come? That's much less than the RRP, even with the £100 pre-order discount.

3 hours ago, Simone_DB said:

Speaking of this anyway, do you think a barlow lens could help, when I want to make observation, and take that off during photography sessions? Or are there any other workarounds that could make the instrument more versatile?

In practice, you would be using a Barlow lens or exotic eyepieces to gain enough magnification for many visual observations.  If you are observing from a light polluted location, this will bias you toward observing small bright objects (double stars , planets, etc), for which a scope with a native long focal ratio would be more suited, e.g. a f10 SCT. 

As I hinted earlier, you should not give much weight to the idea of a versatile instrument.

You need to think about what exactly the telescope is for.  I assume these f4 Newtonians are intended for astrophotography - for which the only difference between the 150 and the 200 will be the image scale.  The 200 will be more affected by wind and more of a load on the mount.

What exactly do you want to image? Some popular targets will be too big to fit in the field of view.  You will also need potentially expensive accessories, e.g coma corrector, guidescope.

If you can, buy the book 'Making Every Photon Count' by Steve Richards.

For visual use, I suspect f4 is less than ideal.  Likewise it is less than ideal for planetary imaging.

Trying to make 1 telescope do all things rarely works well.

If you want an easier introduction to deep sky imaging, putting a DSLR on a tracker mount is probably the way to go.  (or on the HEQ5, since you already bought it.)

Budget? And what exactly do you want to image? Constellations? Nebulae? Planets? Remote galaxies?

I have found partial answers to my own question.  Earlier editions of the Seestar app and firmware, including those I used for my 'first light', only let you save stacked FITS images to the S50.  Later editions, now available, apparently let you save an array of FITS images (i.e. not stacked).

Various beta testers (who did not tell us what app and firmware versions they were using) evidently had advance copies of the non-stack versions, and posted Youtube videos explaining how to stack the files and then process them (usually with Siril).  If you have stacked FITS S50 images, you can just skip the part of the instructions where they tell you to stack the images.

The FITS images are dark, and require a considerable stretch (or auto-stretch) before you can see much.  A simpler workflow I discovered is to open and stretch the image in ASTAP, export as a TIFF and then process it in GIMP.

If you can't make it work with the handset, making it work with wifi and dongles will be even harder work.

You need to enter the right data in the right format (a common source of newbie error.)

And then grasp the over-riding principle of the alignment process:

1) aligning north and horizontal gives the GoTo a coarse starting point.

2) it moves to the first alignment star, hopefully accurately enough so you can see it in the finderscope.

3) fine-tune the aim and go for the second alignment star and repeat.

4) Don't use 3-star align - 2-star is easier and will get you started.

IIRC there are alternative setup processes in the handbook, but it is probably best if you can identify a few bright alignment stars (e.g. Capella) and use those.

In the real world of bad seeing,  a 2.9um pixel camera and f12 would be close enough. 

I use a 2.9um camera and a f10 SCT. I tried using a barlow but it did not confer any evident advantage and was harder to aim.