johnturley

17 hours ago, Mark2022 said:

So what do you use now? I was thinking how I might build one but I don't have the tools and skills but I'd give it a try. It doesn't look that bulky.

I'll give you a laugh: I was even looking at how big you can buy "Lazy Susans" because I've just built (built isn't  the word really - it's just laying one brick on top of another) a "Todmorden" pier in a flip top roof  'shed' I built and I thought "Wouldn't it be fun to have an observing chair on top of a Lazy Susan so, when you slewed to a different object,  you don't have to move your bum an inch!"

I actually have a Nadira folding chair now which I purchased from Rother Valley Optics, its not ideal but it does fold up small.

I also have some steps on wheels, on which I place my laptop when doing astro-photography, I just couldn't wheel them around the shed with the original bulky observing chair in place.

John 

3 minutes ago, Mark2022 said:

Is that a dIY chair I see there?

It was made by a carpenter friend some years ago, based on a design in a old Patrick Moore book, but I don't use it now as its rather bulky.

John 

4 minutes ago, Mark2022 said:

John, do you have a pic of your Astro Systems 14 inch? I bought an 8.5 inch way back when when i was just out of uni at about 21. The wife was so happy when i sold it! I won't  curse!

I won an Astro Systems caption contest soon after and had a choice of a Celestron SCT and £1000.  I took the £1000 because it would pay for the honeymoon and I'd already bought the Reflector. Patrick Moore handed me the cheque when he was  in Edinburgh! Good times!

This is possibly one of the best photos taken at the time I had an Astro Physics (early pre-Starfire) 6in f8 Refractor piggybacked. I now have an Esprit 150 piggybacked, it might surprise some, but the Esprit 150 is much better colour -corrected, and gives sharper images. 

John 

3 minutes ago, Elp said:

Also, if you bin2 the image (half the image size) you might find it actually looks a little better (but small on the viewing device), certainly works when I'm looking at smallish nebulae.

Binning didn't give good results on planets when I've tried it.

John

10 hours ago, Mandy D said:

I've no doubt you are, but you will not, except, maybe, perhaps under truly exceptional seeing max out the benefits of 2x Barlow on an f/10 with 2.9 μm pixels. Physics is working against you, here. Scale your image to 75% and it will be closer to 1.5x Barlow and some of the blurriness will disappear. I doubt you have gained extra detail (byond a 1.5x Barlow) by using such a long focal length with that size pixels and that scope under the seeing you appear to have at your location. A 3x Barlow is simply going to give you a harder time focusing and controlling vibrations, etc. But, of course, this is my opinion only and you are free to go whatever way you like.

It's a bit like saying that a magnification of 50-100x with a 6-12in telescope on Jupiter will reveal all the detail that it present, but most people consider it more aesthetically pleasing when viewing conditions permit, to view it with a magnification of 200 - 300x. 

John 

18 hours ago, BGazing said:

Seeing looked rough and I was tweaking focus between captures endlessly...so was kinda surprised to see this result. Video derotation 6 minutes, 12K best frames (about 25 percent of the total). C11 again, still have not returned it.

Comments and suggestions welcome, on processing especially, always looking to improve.

 

Looks like, due to Jupiter's varying inclination (only 3 degrees though), Ganymede is only just touching the Jovian disc, I assume Callisto will be missing it completely. 

John 

Sounds impressive, and at a very competitive price too at around half the price of the Esprit 150 (and lighter too), and less than 20% of the price of a premium 6in Refractor such as the Tak TOA 150, or TEC 160.

I think that it is very similar (if not identical) to the TS 150 

John 

On 27/09/2023 at 22:32, John said:

If I was purchasing a triplet refractor then I would probably arrange to pick it up myself rather than trusting it to a courier, even if it had been checked prior to sending. 

I am planning to get a Takahashi 100 DZ Refractor after selling my Celestron CPC 9.25 (selling due to back problems), and although I usually buy most of my Astro stuff from FLO, I will probably get the 100 DZ from Rother Valley Optics (who are just 15 miles away from me), so that I can pick it up in person, so as to avoid the risk of any possible damage or misalignment of the optics, due to rough handling by the courier. When I purchased my Esprit 150 (from FLO), this was 'drop-shipped' direct from OVL (the UK Skywatcher distributor) to ES Reid for testing, and I arranged to pick up the scope direct from ES (whom I know personally) after testing.

I will however, probably buy the tube clamps and saddle plate to attach the 100 DZ onto my AZ-EQ5 from FLO, as they offer a better choice which are more competitively priced. FLO also appeared more knowledgeable than RVO in so much as they  pointed me towards an adapter bar to enable the attachment of the Takahashi cradle to the AZ-EQ5 mount, whereas RVO said that it wasn't possible. Utilizing this adapter bar with the Takahashi Cradle, however works out more expensive than the StellaLyra 95mm tube clamps, and I gather is also less stable. 

John 

On 28/09/2023 at 13:16, johnturley said:

Thanks for the info.

I have now successfully placed an order with Harrison Telescopes, so remains to be seen whether they will actually be able to supply one.

Assuming it does arrive, I will compare it with my 36mm Aspheric, and 56mm Meade Plossl, and if it compares favourably, possibly sell both of these. My Meade 56mm Plossl is actually one of the original 5 element made in Japan eyepieces, so may fetch a bit of a premium price.

John 

Just received notifications from Harrison Telescopes, that they have now shipped the 42mm Vixen LVW.

Although their website showed that this eyepiece was available, I did have my doubts as to whether they would be able to supply one, as Vixen ceased production some time ago, none of my 'usual' retailers were listing it, and it does state on their website that this product comes direct from their supplier. In fact its still showing up as available in case anyone else had thoughts about getting one.

John 

55 minutes ago, lawsio said:

This is what I've based the above comment on ^

 

 

As some have mentioned previously, it is not possible to get a 52 degree field with a 1.25in 40mm eyepiece, unfortunately some manufacturers do overstate the apparent field of view of their eyepieces, or quote the average for the range, and the longer focal lengths have smaller APFOV's. 

John 

Astronomy Now, as it is based on a UK perspective, and only lists for example phenomena of Jupiter's satellites that are visible from the UK. 

John 

Just now, John said:

I did not think too highly of the Aspheric 36 that I had and that was in an F/12 refractor. I could still see some astigmatism towards the field edges.

I don't find the Aspheric 36 too bad in my f7 Esprit 150, but the edge quality is rather poor in my f5 Newtonian, hopefully (assuming that it arrives) the Vixen 42mm LVW will be better in both, besides giving a slightly wider field of view.

John 

23 minutes ago, Mr Spock said:

According to this http://astro-talks.ru/forum/viewtopic.php?f=32&t=1483#p41976 the aspheric has very bad image quality. The 42mm LVW does ok and the other LVWs rate as excellent image quality.

Thanks for the info.

I have now successfully placed an order with Harrison Telescopes, so remains to be seen whether they will actually be able to supply one.

Assuming it does arrive, I will compare it with my 36mm Aspheric, and 56mm Meade Plossl, and if it compares favourably, possibly sell both of these. My Meade 56mm Plossl is actually one of the original 5 element made in Japan eyepieces, so may fetch a bit of a premium price.

John 

18 hours ago, Mr Spock said:

The LVW range was discontinued a few years ago. You'll probably only be able to find one used. Generally it's a very sharp eyepiece, but, it does have some astigmatism round the edge; it also has uneven magnification - it's 42mm in the centre but 34mm at the edge. This is why there's confusion over the field of view - it is 72° but at an average of 38mm not 42mm.  Some are labelled as 65° but that isn't right either - at 42mm it's the equivalent of 65° but that isn't the right way to do it. I wish they had just labelled it as a 38mm 72° eyepiece. Sounds confusing - you'll see what I mean if you look through one. The fov is huge compared to a 'normal' 65° LVW. You can calculate it back from the 47mm field stop.

According to Harrison Telescope's website they still list the Vixen 42mm LVW with availability in 5-7 days, and tried doing a dummy purchase and it went into my basket, but not sure whether they still have one in stock. 

Even if they still have one available, I'm a bit undecided as not sure whether it would be a significant improvement over my 36mm Aspheric.

John 

5 hours ago, Mr Spock said:

The 42mm LVW has a field stop of 47mm  I had a WO diagonal and it vignetted noticeably - I can't recommend that diagonal or its clones to anyone.

 

 

Mr Spock

Do you have a 42mm Vixen LVW, I was wondering what the edge performance would be like in my f7 Esprit, I assume that it would be superior to my Baader 36mm Aspheric.

I already have a StellaLyra 30mm UFF, which I use as my lowest power through my 14in Newtonian, hence was thinking of using in my Esprit (which is piggybacked on the Newtonian) at the same time, and selling my 36mm Aspheric, and possibly also my 56mm Plossl.

Not many suppliers currently list the 42mm LVW, so wondered whether it had been discontinued, in which case if I want one, I need to order it fairly soon.

John 

14 hours ago, lawsio said:

Thanks for this. I notice a few comments refer to the weight of it. I plan to use this mostly on the AZ5 Deluxe mount that comes with the ST, and potentially on the AZGti I already have. Is this going to be OK?

Although the 30mm UFF is no lightweight at around 550g, it is considerably lighter that a lot of other equivalents, such as the 24mm ES 82 at around 800g, or the 31mm Nagler or the 30mm ES 82 at around 1.2kg.

John 

On 18/09/2023 at 15:56, PeterC65 said:

The goodies have been coming thick and fast over the last few days ...

A SynScan WiFi Adapter to see if I can control the SynScan AZ GOTO mount from SkySafari running on an Android tablet.

I'd mentioned in a recent visual observing report that I missed having the Stellarium sky chart to hand when doing visual, after doing lots of EAA recently, and using a sky chart on a tablet was suggested. I already have SkySafari and some playing with this and advice from other SGL members suggested it could be a good idea.

Since I was paying the FLO postage charge, I thought I'd also add a StellaLyra UFF 30mm eyepiece to the order.

To be fair, I've been contemplating one of these for even longer than it took me to order the FMA135.

I've not been happy with the Baader Hyperion Aspheric 36mm and wanted something better for widefield. The Aspheric is fine with the Mak at F11.8 but, frankly, rubbish with the refractor at F6.0 which was its main purpose. For a long time I had decided that 30mm was just too close to my Explore Scientific 24mm, but this StellaLyra is supposed to be super-flat, and I finally decided that a super-flat slightly larger field of view would be worth having.

I think I will keep the Aspheric for the Mak as it widens the field of view significantly with that scope (the Mak has been modified to give it a 2" visual back).

The UFF 30mm is quite a lump, heavier than any of my other eyepieces by the feel of it.

 

The 30mm StellaLyra UFF, although no lightweight at around 550g is considerably lighter than the ES 24mm (around 800g), and I much prefer it to the latter through my 14 in f5 Newtonian. I also prefer it to my 36mm Baader Aspheric, stars being much sharper near the edge of the field. The 36mm Aspheric is not too bad though through my f7 Esprit.

On 11/09/2023 at 15:56, badhex said:

Actually, I meant to add that if anyone fancies joining in on the Enceladus challenge i.e.  seeing what aperture is required to observe it, I would love to hear anyone's results!

I used to find Enceladus fairly easily with a 10in Newtonian in the 1970’s, but now struggle with a 14in Newtonian. I put this down to  combination of increasing light pollution, and my deteriorating eyesight. In addition Saturn was higher in the sky for most of the 1970’s.

Likewise I have never been able to spot Neptune’s Triton visually, although some people (no doubt with darker skies, and better eyesight) state that they have been able to spot it through a 6in telescope.

John

5 hours ago, josefk said:

it was good sport last night trying for Saturn's Moons. Rhea, Titan and Lapetus were observed. Rhea needed Saturn holding out of the EP  FOV to first see it then i could pick it up with a little averted vision even with Saturn in the FOV. I couldn't repeat the trick with Tethys, Enceladus or Dione. A good test of reflections and glare in the EP barrel 😉

What size scope was that with, the other night I found Rhea fairly easy with my 150mm Refractor, but could could only spot Dione through my 14in Newtonian. As mentioned earlier, in the 1970's I found Rhea, Tethys, and Dione, and occasionally Enceladus, fairly easy through my then 10in Newtonian, but then Saturn was higher up, my eyesight better, and skies less light polluted. 

58 minutes ago, John said:

 

I'm looking forward to having a look at Neptune's moon Triton and trying to spot Uranus's brightest 4 moons when those planets are better positioned from my back yard. 

I've never been able to see Triton, or any of the moons of Uranus visually, even through my 14in Reflector going back to the 1980's, when my eyesight was better than it is now, and when I found the fainter moons of Saturn much easier spot than I do now.  It will depend to a certain extent on how light polluted your location is.

John 

18 minutes ago, powerlord said:

So, I noticed that tonight I could get a nice moon in the same frame as Pleiades which would look awesome. theoretically.

Of course practically.. it would need composing and even then would I actually get any detail of Pleiades dust ?

I'm thinking it's probably a lost cause - and if you are going to composite it, you might as well shoot the moon seperately on a night it's not right next to it, Pleiades on a night when the moon is not right next to it, and composite it up to at least 'look' like it could look if we were not at the mercy of moon light pollution in the atmosphere..

What do you reckon? I mean obviously shooting the moon bit is easy - some short exposures, job done. But I'm pretty sure that when I take 60-120 sec exposures the light pollution off the moon is just going to wash out everything else in the frame.

With 2 or 3 nights forecast of clear skies and good seeing I'm trying to plan what I can to maximise them, so don't really want to be experimenting... M57, NCG6823,  NGC6543, NGC7293, jupiter and saturn are all on my list - I feel a bit like a kid in a candy store after so long with crap weather...

If you try to photograph the Moon and the Pleiades in the same frame, I think that you will find the light from the moon will swamp out the Pleiades most of the time, the exception would be when there is a thin crescent moon close to the Pleiades in the evening in the spring, or around July in the morning sky. 

John  

8 hours ago, inFINNity Deck said:

Hi John,

 I do not mention chip-size simply because it is irrelevant. If you do not want that black space around the object, simply crop it in the post-processing. None of the planetary images I show on my website are shown at the actual image size they were imaged at, most of them have a larger background than original, while almost all have been resize by that 200% I mentioned before in order to make them a decent size for viewing.

The point I try to make is that, when using an optimal focal ratio, the exposure times go down significantly. Had the image been made at about f/9, the exposure time would have been 4 times as low, resulting in a higher frame-rate and thus more data in the same time-span (and thus a better signal-to-noise ratio had the same percentage of frames been stacked).

Nicolàs

 

You state that the chip size is irrelevant, but the general consensus on this site appears to be that for planetary imaging you need a camera with a small sized sensor, and that digital SLR’s are not ideal for planetary imaging due to their relatively large sensor size. If this were not the case, then why would some observers have 2 or more cameras one with a small sensor for planets, and one with a larger sensor for deep sky objects, if the camera with the larger sensor would suffice just as well for both.

Having said that, I accept that for a given optical arrangement, the size of the image on the sensor will be exactly the same regardless of the size of the sensor, or the degree of cropping used. It appears to be that the software used for image viewing just displays the images taken with a small sensor and/or cropped as being larger, which makes them more aesthetically pleasing, and easier to process. I would love to see a large detailed planetary image taken with a digital SLR, using no more than a 2-3x Barlow for amplification, which you and some others say is possible.

Some observers are also of the opinion that around 2x oversampling gives better results than the theoretical optimum of around 3x the pixel size. I suppose it’s a bit similar to saying that with for example a 6-12in aperture telescope a magnification of about 50-100x is capable of revealing all the planetary detail that is there, but most observers find under good conditions, using a magnification of 200-300x more aesthetically pleasing.

I will however try doing some imaging closer to what should be the optimal focal ratio, using additional cropping or the drizzle function in Autostakkert to increase the image size to see whether it does give better results

John  

Last night had my best view of Saturn this apparition, and look my first image, taken through my Esprit 150 using a 2.5x Powermate, and processed in AutoStakkert and Registax, and a bit of polishing in Lightroom.

P.S. I have processed another Sharpcap video since this morning, and attach the latest one, which I think is somewhat better than the original.  

John 

7 hours ago, inFINNity Deck said:

Hi John,

good point, sure there is a difference, so let's have a look at the maths.

Pankaj plans to use a 10" f/5 Newton with 2x Barlow and his Canon with 4.3 micron pixel-size. That combination yields a resolution of 4.3/(25.4 x 10 x 5 x 2) x 206.3 = 0.349"/pixel. Currently Jupiter is about 44.36" in apparent diameter, so that is 44.36 / 0.349 = 127 pixels on his camera. Now he should be imaging between f/12.9 and f/15.9, so should be using at least a 2.5x Barlow (f/12.5). Using that Barlow he would get a planetary diameter of 127 x (2.5/2) = 159 pixels (3 x Barlow would make this even 190px). In my set-up this would become about 204 pixels, so indeed significantly larger (about 28% more than with with the 2.5x Barlow), but not a whole lot, and even insignificant if he would use a 3x Barlow. The diameter of Saturn with rings is approximately equal to Jupiter at the moment (44.14" vs 44.36"), so that planet would give the same results. The planet itself (i.e. the globe of Saturn) is of course quite a bit smaller, that would become 67 pixels would Pankaj use a 2.5 Barlow (81px when using a 3x Barlow).

Above images of Mars were taken on 26 December 2022 while it was only 15.35" in apparent diameter, so a third of current Jupiter and Saturn and thus only about 75 pixels in my 3 x [pixel-size] set-up, so approximately the same size as the Jupiter that Pankaj can image with his set-up.

Nicolàs

Nicolàs

You make no mention of sensor size or capture area, I don’t know by how much, if at all, you can crop the capture area with the Canon 1200D, but it will be almost certainly less than with a dedicated planetary camera. So if Pankaj uses his 10" f/5 Newton with 2x Barlow and his Canon 1200D (Aps-C sized sensor 24x18mm), using no more than a 2-3x Barlow for amplification, then I think that he will be disappointed with the resultant small image size.

My first attempts at imaging with my ZWO ASI 462 Planetary Camera (which has a sensor size of just 5.6 x 3.1mm) through my Esprit 150 weren’t that great, as I didn’t appreciate that you need to crop the capture area to get an image that appears to be of decent size.

My first attached image taken in August 2021, shows the result of an uncropped image at the native f7, which isn’t actually far from what is supposed to be the optimum of 3x the pixel size of 2,9 um. Although the size of this image can be increased using post processing software, I found that if I tried to do this by more than 2x, the results weren’t great.

The second attached image was taken with the same setup, taken in October 2022, but using a 2.5x Powermate, giving f17.5 (nearly double what is supposed to be the optimum), and cropping the capture area, giving a much larger apparent image of reasonable size. I think that you will agree that the second image, which shows the GRS, is much better showing far more detail.

The third attached image taken in August 2020 shows what I achieved using eyepiece projection (I think that I used a 12.5mm Plossl) with a Canon 6D full frame digital SLR,  if I had just used a 2-3x Barlow, the image size would have been much smaller. At the time Jupiter was quite low down, and it was more difficult to focus through the camera viewfinder. 

John 

3 hours ago, inFINNity Deck said:

Hi John,

Please note that there is a difference between "a decent sized image" and an image with maximum detail. The formula 3 x [pixel-size] (or 3.7 x [pixel-size]) gives the focal length at which the maximum detail is recorded. Going above this means that no additional detail is recorded while exposure times go up drastically (quadratic with the amount of oversampling, so going from a factor of 3 to a factor 6 increases exposure times by a factor of 4!). It is for that reason that I stick to the formula and create a decent size after processing by using a bicubic resize of 200%. I have been testing this with a ASI290MM and found no advantage detail-wise when compared to the ASI174MM that I normally use. The pixel-size of the ASI174MM is twice that of the ASI290MM (5.9 vs 2.9 micron), so I resized the ASI174MM images by 200% after stacking to make them the same size in below image (all imaged at f/20 with a C11 EdgeHD). The image at the far right is the same as the one at the centre, but with additional sharpening (bit too much to my liking, but it was to see what happens in the image analysis):

 

 

Nicolàs

Nicolas

But you are using a C11 Edge HD (focal length 2,800mm), I think the situation would be somewhat different for someone using a much shorter focal length instrument, say 500 - 1,000mm, or a much larger sixed sensor than your ASI 174, or ASI290, as with a digital SLR.

John