Cosmic Geoff

Another effort, on 24 Oct.  This time I made a stack of 100 images, which gives a slightly sharper result and (on the imaging laptop) I could see four moons and no interfering stars. Moons identified with the Sky & Telescope tool. Image non-inverted.

Taken with CPC800, ASI224MC (and flip mirror).

I should just point out that I put together a 200mm Newtonian and manual EQ-5, and took an instant dislike to it. The eyepiece got into awkward positions, and I had to choose between tripod legs retracted (low objects blocked by fence) and tripod legs extended (needed a cherry picker to reach eyepiece 7 ft above ground for some high objects.) Aiming the straight-thru finder was almost impossible on high objects.

I soon bought another 8" scope I could actually use - an 8" Goto SCT. 

Also you should check out the potential of EEVA (electronically assisted visual astronomy).  With this I've 'seen' objects beyond the reach of a visual telescope twice the size.

When I was a youth I made an 8" f7 Newtonian from scratch, including grinding and polishing the mirror. I remember the grinding tool was squares of 1/4" glass stuck on a round wooden disk with pitch.  IIRC I was working on a conventional workbench and rotated tool or mirror at intervals by hand.

Looking back, I am amazed that I managed it and that the completed instrument worked (I'm not sure how well 🙄).

Here's my not very good image, with the identifiable blobs marked.  This image is the 'right' way up, non-reversed.  Note that with a SCT if the camera is not looking through a diagonal the image will not be mirror-reversed.  Some of the objects in Stevewanstall's image are stars, others are moons.

On 22 Oct I had a go at EEVA with the moons of Uranus, using my CPC800 and the ASI224MC (and flip mirror)

The image with about 5 sec exposure looked exciting, with several little dots in a line around Uranus's overexposed blob.  But when I analysed it later I found that I had imaged several 13th mag. background stars, and noted Oberon as a definite ID and Ariel as possible.  The seeing was bad.

The moons are clearly within the range of this setup, so I will try again sometime and see if I can secure a set of stackable images.  The Sharpcap live stacking wouldn't work on this occasion.

I needed Calsky to identify and eliminate the background stars, but it unhelpfully notes the moons as 'beyond the range of amateur telescopes.'  The Sky & Telescope tool identified the moons.

Seems you are talking about 'electronically assisted visual astronomy'.  Be aware that this is a field for which no turnkey or off-the-shelf solutions exist yet, though many of us have experimented with various combinations of kit, often to our own satisfaction.

From my own experience, I can point out some pitfalls.  For the Moon and planets, your students may be under-impressed by the fuzzy, trembling live video view of a planet. A stacked image from the same data will reveal far more detail.   It is quite difficult to get a telescope aimed accurately enough for a planetary close-up (e.g. Jupiter part filling the screen), possibly beyond the capability of remotely controlled GoTo.  Unlike with visual, you can't change the field of view width. The field of view for a high resolution planetary image is exceedingly small.

If you use a wide-field setup (small widefield scope + planetary camera, or longer focal length scope + large sensor), you can use GoTo with some confidence that the desired object is in the field of view.  With a minute or so of live stacking, quite faint objects can be seen.  I have been astonished at the performance of a 102mm f5 achro refractor coupled with a ASI224MC camera.  On a cheap Goto mount it showed galaxies fainter than mag 11 and imaged a starfield including the minor planet Pluto (m14.3).   Whether your students will be impressed remains to be seen.

I have A CPC800 and find it is excellent for planetary astrophotography - solid as a rock, tracks well, etc. In fact I bought it mainly for this purpose.  As others say, I suspect that putting a CPC1100 on a wedge (etc) could be more trouble than it's worth.

You could put it on an equatorial mount, but this would have to be massive (and non-portable).  Better to start with the small-aperture ED scope as suggested above.  In astrophotography, aperture isn't king. 

I actually tried projecting Mercury at the time of the last transit a few years ago.  I set up my 102mm f5 achro refractor, which did not quite manage to resolve Mercury's dark dot.  I switched to projection using my 127mm Maksutov, which resolved Mercury's dot okay - by now some way inside the solar limb.

Lesson one: inferior optics will not be good enough to show Mercury. 

Lesson two: you can use a 127mm Mak. (I would not advise using any larger aperture telescope).

Lesson three: don't use an eyepiece with plastic body elements - they tend to melt if you get the Sun off-axis.

Projection screen - you do not need anything special - a white fine grained card will work just fine.

If you use a diagonal it saves the bother of making a sunshade for the projection screen - just hold it so the sun does not shine on it.

What camera?

If you use Windows 7, you will soon be receiving notices saying that support will end in Jan 2020 (if you have not had one already.)  That means no more security updates.

A large number of Windows users are still using Windows 7.

Microsoft want users to upgrade to Windows 10.  The reaction of many will be No Thank You, because they don't fancy paying for a new licence, or suffering the performance of Win 10 on an ageing machine. (I tried Win 10 on an older desktop, but after a while got fed up with its sluggish performance and reverted  to Win7. Much faster.)

Here's my tentative to-do list:

I recently acquired a new-ish desktop with Win 10 installed, for those tasks where an old machine won't cut it.

The 'everyday' low power desktop - for email, browsing and wordprocessing only, I'll look at switching to Linux.

Older spare machines - do nothing.

Imaging laptop (Dell Vostro 3400) - do nothing.

Any reactions?

If you are into serious DIY, consider making a proper equatorial mount with RA drive. Amateur telescope makers used to do this in the days before Chinese-made mounts and credit cards.  Or keep an eye on the second-hand market and see what comes up. 

A budget alt-azimuth GoTo mount (e.g.  Celestron Nexstar SLT or Skywatcher Synscan) will work quite well for short exposures with a small telescope, if you fancy that route. See my posts under EEVA reports.

I bought a 15mm Celestron Omni plossl to use with mine.

The focal reducer will give you a wider visual field. Alternatively you could get a 32mm or 40mm eyepiece.

As for AP,  I suggest you think of getting some entirely different kit.   The OTA is best suited for planetary astrophotography, and the SE mount it not suited for any sort of astrophotography at all.

Good advice above. 

People do perform astrophotography using the somewhat similar 130PDS Newtonian reflector, but mounting it on suitable powered equatorial mounts that cost far more the entire Heritage 130 outfit.  For general astrophotography, a DSLR or an expensive large-sensor astro camera would be used, and for planetary astrophotography a small-sensor planetary astro camera (+Barlow) would be used.

The question for you therefore is: how much are you prepared to spend?  If the Heritage has a standard dovetail, it could be re-mounted on a better mount.  What 'better mount' means is up to you, but a really good one would leave little change out of £1000.

I think you are worrying about something that 99.99% of SCT owners don't worry about.  The manufacturing tolerances of the corrector and secondary supports should ensure that it is well enough centred for the purpose.  There has been some discussion here about whether the angular position of the secondary mirror is critical, should it come loose, but the general opinion was that the recent secondaries are well enough figured so that the angular position should not matter. 

Some SCTs are said to perform better than others, with the finger of blame being pointed mainly at some older production runs (of a particular make). But I have found that at an 8" size the main limiting factor is the atmosphere. 

Depends what you think you want out of the hobby. There is no 'right' answer.  Some people like the simple approach and swear by 'learning the sky'. Others like lots of tech.

Personally I have never seen the point of 'learning the sky' and most of my observing projects involve the use of GoTo.

Equatorial mount - for the beginner a manual equatorial is probably more trouble than it's worth. A motorized equatorial would be handy for visual observing.  Heavy duty equatorial mounts (nearly always GoTo these days) are used for serious astrophotography.

 Also be aware that modern electronics and cameras can considerably enhance the reach of even a small telescope. GoTo makes faint objects rapidly findable. Planetary imaging can reveal detail that is hard to even glimpse visually.  And if you see what a small scope set up for EAA (electronically assisted astronomy) can do, you may start to wonder what's the point of a bigger scope, at least for fainter objects not requiring high resolution.

Visually observing the planets may not occupy you for very long.  For £500 you can definitely buy something that will let you see some bands on Jupiter and glimpse its Great Red Spot, and the rings of Saturn and lots of detail on the moon. Somewhere on this site is a guide to 'What can I see?' But once you have looked at these??

You can explore the deep sky with a Dob, but it is a lot easier to find stuff with a GoTo mount.  The latter may involve choosing a smaller telescope to keep within your budget.  Some people though don't get on with GoTo mounts or prefer the old-fashioned simple method.  Personally I would not be without a GoTo mount as most of the things I want to try would be difficult, excessively time-consuming or impossible without one.

There isn't any 'best answer' when buying a telescope as it is largely a matter of personal preference.

It clearly rains more in some parts of the country than in Bucks. 🙂 My lawn looks rather brown in summer and it never gets boggy.  I have a line of paving slabs running alongside the 'observing' area of the back lawn, so that I can tramp to and fro on them or try to place the stool there.  Paving slabs can be a mixed blessing for tripods as they shift if you put your weight on the slab.

There is also Meade's new LX65 series, with ACF optics and a single arm mount that can mount two scopes.  An 8" model costs about £1300.   There are some reviews of it online.   

Is ACF the equivalent of Celestron's Edge HD?  An 8" Celestron Edge HD costs around £1300 without any mount.

My experience of Celestron SCTs and Maksutovs is that they work well optically and if the mount develops a minor problem I can fix it myself.  Spares seem to be available for bigger problems, should anything occur. No reason to switch brands so far.  Thousands of happy owners can't be wrong.

As for Meade, never used one, less familiar, confusing model identifying scheme, rumours of mechanical problems.

Primarily for visual use?

The Celestron C8SE is a popular setup, and a good visual instrument, and portable (one can pick up the whole assembly and carry it through a standard doorway)

However as a C8 SE owner, let me disillusion you of the notion that it is any good for imaging. Using it for planetary imaging is a pain and for deep space imaging, even worse.  If you intend any sort of imaging, get a C8 tube assembly and mount it on the heavy-duty GoTo mount of your choice.   The CPC800 version works very well for planetary imaging, but a German equatorial GoTo would be a more flexible choice.  Attempting deep-space imaging with a scope of 2 metre focal length is by most accounts not for beginners, regardless of what the manufacturer may imply.

As for the LX90, I know nothing, but take a critical look at the mount and tripod.

The wedge seems to be getting the thumbs-down here. As an engineer, I can appreciate that using a wedge could add more stress to a consumer-grade mount.  Perhaps the best answer is to mount it as an alt-az but design the setup/pier so that a wedge can be added later if desired.

The wedge for the OU LX200 telescope is a fixed one, apparently welded up from angle iron.

An equatorial mount (wedge) will get any images in the correct RA/Dec orientation, which may be a consideration for your purpose.

I took an image of the 'africano' comet with an alt-az mount and it is skewed by about 45 deg which made the image harder to interpret.

Africano captured EVA style with 102mm f5 Startravel achromat, ASI224MC on SLT mount.   Field is angled around 45 deg to lat/long. Comet near bottom of frame next to TYC2285-216-1

19 Sept around 22.30 BST

6 minutes ago, tooth_dr said:

In term of future proofing - is this solely for deepsky imaging with long exposures?  I'm just trying to rationalise the spending versus what benefits it brings.  It would raise the overall height of the scope for viewing too - not sure if this is an advantage or disadvantage?

I was thinking of the deepsky imaging with long exposures option.  IIRC the eyepiece height of the OU instrument is suited to standing observers - a bit high for a child.  The wedge is triangular (a fixed welded sub-frame) and I don't think removing it would make the instrument significantly lower.

1 hour ago, tooth_dr said:

Is there any advantages to fitting a wedge?

Future proofing.

I have seen the 16" LX200 Meade at the Open University observatory, and that sits on a wedge.