Xilman

1 hour ago, Gerr said:

This is one of the highlight images of my recent trip to this beautiful island in the Canaries. There is virtually no chance of me capturing the Milky Way Arc like this in the UK.

I took the image at 3am (10th Jan 2024) on top of the volcanic caldera, Roque De Los Muchachos, 8000ft high.  Canon6D, Rokinon 24mm lens. The sky was tracked. 

Foreground images (six taken in landscape orientation) at ISO 1600 120secs f2.8.

Sky Images (11 images in portrait orientation) at ISO1600 70secs f4.

Hydrogen alpha (4 images taken) at ISO3200 150secs f2.8.

Processed in Lightroom and blended in Photoshop CC.

Hope you like (CC's welcome).

Milky Way Panorama - Roque De Los Muchachos:

Shame I didn't know you were coming over because I arrived back in LP on 11 January and we could have met up.

The lights of Los LLanos are visible (they shouldn't be, some people are breaking the law) and my house & observatory is hidden by the small peak to the left of Los Llanos.

Note also the colour and the unusual brightness of the sky to the south, Bortle 8/9 perhaps --- the orange Na glow in particular. We have been plagued by calima (translates as "dust") which blows in from the Sahara. A calima generally brings hot weather (it reached 26C towards the end of January here in El Paso, when 18C is more typical) and rather poor visibility. El Roque is above the inversion layer and so doesn't suffer too much but where I am is 760m above sea level and sometimes the naked eye limiting magnitude is around +1. When only two stars in Orion, Rigel and Betelgeuse, are visible to the naked eye, there's no point in trying to observe anything.

Rock of the boys.

The boys in question are several pinnacles of rock, now sadly eroded by tourists taking souvenirs.

Roque also means "rook" in the context of the game of chess.

Do you collect artifacts? If so, they are undoubtedly valuable. Otherwise, YMMV.

I make good use of both bits and atoms. There are a number of ways in which physical representations are more useful in practice than their virtual counterparts.

Horses for courses.

Have you read The Road to Reality yet?  Damned fine book, IMO, but can be heavy going after a little while.

If you like that one, you will probably enjoy Gravitation by Misner, Thorne & Wheeler - almost universally known as MTW. Nice pictures and helpfully split into an introductory and an advanced track, the latter of which can be safely skipped.

Well, observing was a waste of time. When Orion is barely visible to the naked eye because of thin high-level cloud ...

At bottom are binders of sundry VS and supernova search charts, an Interstellarum Deep Sky atlas and a boxed SAO star atlas. Two binders of VS charts not present because I had hopes of observing a few VS tonight.

First shelf contains the SAO catalogue and the Hipparcos/Tycho catalogue, vols 14-16 of which are the Millennium Star Atlas. Vol 2 of Uranometria is the pink one. Vol 1 is in Cambridge.

Second shelf a few random reference works and Sky Atlas 2000. Norton's 2000 generally lives there too but it was next to the TCS monitor this evening in the hope it might be useful.

On top are carry-cases for Starlight Xpress equipment and random documentation for telescope, dome, computers, network, etc.

There's a challenge. I'm off to the observatory now that it is getting dark so will post a picture from there of some of the library. As a taster, here's the books behind me. Sorry for the poor quality.  The blue booklets on the right are copies of The Observatory from the RAS; the issues of A&G are elsewhere. The spineless book is a first (1910) edition of Norton's Star Atlas. I wish it were in better condition.

The vast majority of my library is in the UK and so inaccessible from here in La Palma. It includes works going back to the early 19th century by the likes of John Herschel, as well as more modern books and atlases. I have an almost complete set of BAA Handbooks, several feet of JBAA, several more feet of sundry scientific journals and ${DEITY} knows what else.

Incidentally, the duplicates of BAAH are free to a good home. You collect or pay shipping. Contact me some time after Easter for a list of what is available.

Guy Hurst has been the editor of The Astronomer magazine for many years. He also has an asteroid named for him: (3697) Guyhurst.

The BAA-ARPS subsection (asteroids and remote planets, which includes exoplanets) is observing this body over the coming months in an attempt to determine its rotation period. My first data was taken in the wee hours of 2024-02-02 through a Johnson V filter so that standardized photometry can be performed. That detailed analysis is not yet done but here is a stack of 78 40-second images taken with a SX 814 camera attached to the 0.4m Dilworth telescope at Tacande Observatory, aka MPC J22. The track of (3697) Guyhurst as it moves across the sky during those 52 minutes appears in the centre. At the lower right is a Seyfert-2 galaxy, 2MASX J11075004+0942565, which is catalogued at V16.07.  The predicted magnitude of the asteroid is V=17.3.

On 15/01/2024 at 10:08, bomberbaz said:

Yes never thought about identifying it amongst a see other other stars.  Well over 13 hours RA is stable where as dec it is moving at around 0.65 seconds an hour.  Not sure how this computes into imaging without trailing maximum time?

Turns out to be remarkably easy for something that bright, unless the field is very crowded..  Head over to https://aladin.cds.unistra.fr/AladinLite/ and type in the co-ordinates of the target. Zoom in to a field less than a degree across. In the default DSS2 image stars down to about g=21 will be shown. Switch on the Gaia DR3 display and you can find the magnitudes of the stars in the field. If you then image and stack as you go until you can see stars at least as bright as your target you will be able to identify it in the final stack because you can then do heavy duty contrast stretching.

Actually, I do that before starting imaging. No use even starting if the predicted position is too close to a star as bright or brighter.

On 14/01/2024 at 00:44, bomberbaz said:

Hello all, don't know if this is feasible so I thought I better ask before devoting a lot of effort.

There is an asteroid called "(3922) Heather" in Virgo at a magnitude of 19.3 and given size 20km dia at 3.1 au. Is this doable for imaging? RA 11h 57m 00.76s by dec +00 35' 26.1" as at time of post.

It dioesn't show in stellarium but is in sky safari.

I have no intention of trying myself, it is beyond my own capabilities but I could either use a remote telescope and pay or employ the services of someone on here.

It is for sentimental purposes, something I thought about a few years back but now is the time I see if my thoughts were reality!

Any help or tips gratefully received.

Steve

Should be straightforward with a decent camera and an aperture of at least 20cm. I have imaged satellites in the outer solar system such as Siarnaq (http://www.astropalma.com/Projects/Satellites/siarnaq.html) and Caliban (http://www.astropalma.com/Projects/Satellites/caliban.html) at magnitude 21 or fainter.

You will almost certainly need to take many subs and stack on the predicted motion of the asteroid as it will be too faint to show up on exposures long enough for it not to be trailed.

I am almost tempted to image it myself but that would spoil your fun.  Virgo is a bit late in the night right now, for that matter.

What I do in MaximDL is 90% of what I would do with any software package, such as EKOS. I take lots and lots and lots of images, storing them in a single directory on disk.

Zeroth: clean the optical surfaces, including the camera window. No point in making life harder for yourself and the image calibration process when you are taking science images.

First configure Maxim DL's camera control to auto-save each image taken into a newly created directory and set the camera's cooling to the temperature typically used when observing.

Second take a series of bias and darks, the latter at (usually) 60 seconds each, at each of the binning levels typically used when observing. Somewhere between 20 and 30 of each is generally enough to smooth out most of the Poisson noise. These darks and flats will typically last for months before needing to be retaken.

Third I put a fluorescent panel directly in front of the telescope aperture and try hard not to let any extraneous light leak through.

Then, or each filter likely to be used (including no filter) and at each binning level, take a guessed exposure length and find out roughly how bright is a typical pixel, using the standard MaximDL tool. Then calculate how long, roughly, each would have to be to give 40-60% maximum values. For a 16-bit camera like mine, this would be 25,000 to 40,000 say. Take between 9 and 25 images at each setting (thereby reducing Poisson noise by a factor of 3 to 5).

Finally, after all this you have a directory full of calibration subs. I then convert them to master bias, dark and flat images. The Set Calibration tool has a nice wizard to make the process relatively straightforward. Once the master files are built, I delete the individual subs which form them, purely to save disk space.

All this is well documented on pages 137-144 of the Maxim DL 6 manual.

Of course, once the calibration files are in place the camera control is configured always to use them automatically.

HTH,

Paul

On 15/01/2024 at 18:31, Ludd said:

I made the jump up to a 17.5” dobsonian a while ago and it is just about manageable by a mildly unfit 56 year old with coronary artery disease, short legs and minimal upper body strength (I am a cyclist). I have a few steps in the garden but the main challenge is the width of the base, which almost matches the width of my shed door.  The jump from an 8” aperture was astonishing but it’s not really ideal for quick observing sessions as it requires a bit of setting up, including a stepladder to reach the eyepiece.  I do wonder if 12” would have been more sensible (and cheaper)

Back in the day I had a 18" from Beacon Hill Telescopes. I could pick it up and move it around a little distance but I was only half my present age. I wouldn't want to do it now.

The solution was to build a custom wheelbarrow. A doddle thereafter.

55 minutes ago, maw lod qan said:

Sometimes I leave an eyepiece, capped, in the focuser when parked.

Then I put the covers on the ends of the scope and finder scope.

Started viewing one night, got the moon in the finder, put my eye to the eyepiece and saw nothing!

Finally I took out the eyepiece and laying just below it was a frog, completely blocking the view.

Here in LP is hosted a robotic observatory for a chap in Cheshire. When I am also in LP I do tech support and can recount wild life stories.

Once we were watching a gecko wandering around in the view of the web cam set up to monitor the conditions inside the dome.

On another occasion, the dome would sometimes go to its parked position on request and sometimes it would not.  I hate irreproducible bugs intensely. After some investigation I found that a spider was setting up home between the led and photodiode which the dome controller used to monitor the position of an occulting bar attached to the movable part of the dome. Depending on whether the spider was at home or not the beam would be interrupted and the dome controller would believe that the dome had reached the parked position because it thought the occulting bar had moved into place.

16 minutes ago, PeterStudz said:

An EQ platform has already been mentioned with the OP in another thread so I left that one out. I have a DIY EQ platform (they are so easy to make) and I now couldn’t do without it. 

I was not aware of that thread.

21 minutes ago, Mandy D said:

This is likely atmospheric aberration when the Moon is low in the sky, normally blue and orange, but cannot remember which way up. When you view the Moon higher up with a reflector, you will not see it. The cause is pretty much the same as any other chromatic aberration, except this is caused by the atmosphere, not the glass.

Not all eyepieces and Barlows are as achromatic as perhaps they ought to be ...

One possibility is an equatorial platform.

Not only does an eq platform make visual observing markedly easier, it makes imaging possible.

https://www.skyatnightmagazine.com/advice/build-a-dobsonian-equatorial-platform shows you how to make one. Finding how to buy one is left as an exercise in the use of search engine as I do not wish to promote any particular supplier. 

Some people, Martin Lewis in particular, take absolutely superb images with a Dobsonian. He often shows surface detail on the Galilean satellites of Jupiter, for instance. His web site is https://skyinspector.co.uk/ and a representative set of images can be found at https://skyinspector.co.uk/jupiter/#bwg5/1257

Welcome aboard.

Remember: there are very very few stupid questions.

Unfortunately there are stupìd answers given every now and again but we try to keep them to a minimum and to take corrective action if one should sneak through.

Welcome aboard.

I am technically in Spain right now, but not in the Peninsular. La Palma to be precise.

What looks like a few background galaxies too. For example, the bright spot in blue streak in the spiral arm (itself a HII region) at the 10 o'clock position is the galaxy LAMOST J120312.23+443001.8 and the bright orange streak in the upper left corner is NGC 4013, a 12.4 magnitude edge-on spiral.

Might be clear here later. Roughly 50% cloud cover but very windy. Wind generally makes for lousy seeing, sometimes as bad as 20 arcsec!

2 hours ago, Cosmic Geoff said:

You still have slight trailing at 1 second exposure. Maybe it's not tracking at all? I have regularly made exposures of 20 seconds (tracked but unguided) without noticeable trailing. 

Note that slight trailing will happen if the polar alignment isn't good enough ...

(Edit: ssorry, I didn't spot this point had already been made.)

4 minutes ago, Carbon Brush said:

Alternatively - the spiders catch anything else that is in there😁.
 

Geckos eat spiders ...

4 minutes ago, Carbon Brush said:

You have done well with those images.

Rather than upgrading the EQ3, I would give thought to a larger mount.

Advice which goes back many decades but, sadly, which many people don't receive until after they have spent their budget is as follows.

Spend as much on the mount as you do on the telescope which is attached to it.

Only Dobsonian owners can get away with ignoring this rule.

Professionals have another rule: the observatory building costs as much as the telescope or the mount.

Two things:

Is the motor running too fast or too slow? If so then even if the system is perfectly balanced the stars will still be trailed.

If you add more weight to one side, does the direction of drift change?  If so, you will need to add or subtract ever smaller weights until the drift is acceptable.

A common way of dealing with drift, and I've used it myself quite often, is to take subs with an exposure short enough that the drift is small enough and then stack the subs.

Very occasionally, I deconvolve an image using a PSF taken from one or more trailed star images. This is very much second best, in my experience.

Cobwebs happen. Live with it. A feather duster will remove any which are in the light path.

Over here in La Palma we are much more concerned about gecko droppings, which gets everywhere and is far more damaging than cobwebs. It is essential to keep optical surfaces covered when not in use.

Sorry to be blunt, but that's life.   😉

On 17/08/2023 at 11:22, Alex_Fla said:

Perhaps the title should read " Can't See This with Your Amateur Optical Telescope "

Even a small Radio Telescope can easily detect the Doppler Shift of interstellar neutral hydrogen gas clouds within the Milky Way.

The differing velocities of the Milky Way's Galactic Arms can be resolved and displayed .

 

This is an example of a single ( 5 minute ) scan .. The contour plot was the result of 8 hours of data collection.

Now there's a challenge.

It should be possible to amateur spectroscopists to measure radial velocities of bright stars in different spiral arms. A hundred or few carefully selected stars should be sufficient.

Accepted: it is much easier for radio astronomers.