Search Results for 'espin telescope'

[Peter Anderson]

My C14 (in 2014) came with these bolts to secure the mirror. They were screwed through the back of the tube to secure the mirror fixed in place and needed to be removed or at least loosened so the telescope could be operated.  There were strict instructions that they should not be used to lock the mirror during observations. Celestron said it was okay to remove them completely. (Unless the telescope was to be shifted – which was what they were designed for, they were not to be used.) So I removed them completely and stored them appropriately labelled. I covered the holes with adhesive rubber pads.  I don’t know whether this has helped… Maybe they can be safely used by a responsible adult… Where to get them? Perhaps from Celestron or a dealer. You can see the ‘mirror lock screws’ in the attached image.

I seem to have very little image shift anyway, but my work is not critical. 

[Dr Andrew Smith]

A different take on the dimming: https://arxiv.org/abs/2006.09409

“Betelgeuse is the nearest Red Supergiant star and it underwent an unusually deep minimum at optical wavelengths during its most recent pulsation cycle. We present submillimetre observations taken by the James Clerk Maxwell Telescope and Atacama Pathfinder Experiment over a time span of 13 years including the optical dimming. We find that Betelgeuse has also dimmed by sim20% at these longer wavelengths during this optical minimum. Using radiative-transfer models, we show that this is likely due to changes in the photosphere (luminosity) of the star as opposed to the surrounding dust as was previously suggested in the literature.”

Regards Andrew

[Tim Haymes]

Apologies that this event is not listed on the BAA Handbook Lunar Occ page,  it should have been.  A prediction setting that i used was incorrect. (Fixed now!).  The omission was only noticed after publication.

I will be using an IR pass filter for imaging.   For my mobile goto telescope it should be possible to set up the alignment with stars before sunrise. I might do that and keep the rig running.  Early acquisition of Venus would be a bonus. 

[Jeremy Shears]

Good to see people overcoming the odds and securing successful observations of PQ And. I managed to see it this morning at about 02.25 BST. I decamped with my 12 cm refractor to a field a mile away and it’s far too low from my obsy as you can see from the angle of my telescope in the dawn sky.

[Jeremy Shears]

I just sent out a BAA email alert on this important and rare event:

The dwarf nova PQ And has been reported to be in outburst at mag 10.5 on May 28.776 by Kenji Hirosawa (Aichi, Japan). This means that it is some 9 magnitudes above its usual quiescence of 19.5.

PQ And has only been seen in outburst once before when Dave McAdam discovered it as Nova And 1988. So this is its first appearance for 32 years.

Gary Poyner managed to catch PQ And in the dawn sky this morning: May 29.088 at a visual mag of 10.5 using a 22cm Dobsonian on a wobbly table. Eddy Muyllaert of Belgium also observed it visually this morning at mag 10.3, May 29.080.

All observations of this rare outburst are urgently required, both visual and CCD. Time resolved CCD photometry would also be very helpful. It’s of course tricky to observed given the location in the dawn sky.

Dwarf novae are compact binary stars and as they evolve their orbital period gets shorter until it reaches a minimum around 75 to 80 minutes. The orbital period of PQ And is 80.6 mins. There is some speculation that this might be a rare example of a “period bouncer” in which the system has evolved through the minimum and is increasing.

PQ And is located in Andromeda at RA 02 29 29.55 Dec +40 02 40.0 (J2000.0). A finder chart is available from the AAVSO website. Do try to observe this very rare event. At 10th mag it is visible in a small telescope You might have to wait 32 years for the next one!

Jeremy Shears

Director, BAA Variable Star Section

[James Screech]

I’ve never used anything like 10 minute exposures, the longest I’ve used is 1 min, most of the time I use 10-20sec. 10sec will get me down to around mag 11 with errors about 0.03. I would only accept an error of 0.1 for secondary variables in the same field. Some fields I observe I can get photometry of 4 stars in the same field.

As for DSLR with my setup, a modified 500D with a 200mm f2.8 lens (about 70mm) I get good photometry to mag 8.3 with ISO400 and 20sec green channel only, unguided of an alt-az mount. I use a plan in APT that re-centres targets (with Goto++) about every 1 to 1.5 hours, as it does drift off centre without guiding on a low quality mount. 

Extrapolating isn’t easy as the magnitude will be a function of the camera pixel size, lens/telescope focal length and aperture.

[Roy Lemmon]

Hi,

Thanks very much for your comments and advice. I will have a look at those links.

No. I don’t yet have any of that kit. My aim is to build it up over the next couple of months starting with the mount and telescope, in particular a decent mount. If you have any recommendations, feel free to suggest.

Thanks

Roy.

[Mr Michael Alan Frost]

Hi all,

We’ve produced a special “lockdown edition” of the Historical Section newsletter, which can be downloaded from https://britastro.org/downloads/12387 (you’ll have to sign in to access this). Contact us if you want to be added to the historical section mailing list.

Contents:

Bill Barton has written about two women pioneers from the early years of the BAA. The first five female fellows of the Royal Astronomical Society, in January 1916, were all BAA members. Mary Blagg, Fiammetta Wilson and Grace Cook are quite well-known, but the other two, Ella Catherine Church and Irene Elizabeth Toye Warner are relatively unknown. Bill redresses the balance!

In the Spring 2020 newsletter, Mike Frost wrote an article, When the Dust Settles, about the impact of the 1919 eclipse expedition which verified the predictions of Einstein’s General Theory of Relativity. In this edition, Christopher Taylor responds with Einstein, Eddington and the 1919 eclipse, a fascinating read.

Paul Kiernan, of the National Museums, writes about Liverpool’s very own planetarium 1970-2020: 50 Years of Star Gazing – With the Roof On! Thanks to Gerard Gilligan for suggesting we run this article.

Alan Thomas has contributed several scans from the Ottway Telescope catalogue from the 1970s, which should induce nostalgic memories amongst many of our readers!

… and finally, we have a conundrum for you (based on a suggestion from Tony Kinder)

Only two people have won both a Nobel Prize and an Oscar. Who were they – and which one of them was a BAA member? [NO SPOILERS PLEASE!]

Give up? Read the newsletter!

                                                                                Mike Frost – Historical Section Director

                                                                                Bill Barton – Deputy Director and Newsletter Editor

[Bill Barton]

Telescope not required!

A single shot with both the Moon and Venus on it is what is requested.

[Dominic Ford]

This morning at midday, Dr John Mason presented a live webinar to celebrate the publication of an image by NASA to mark the 30th anniversary of the launch of the Hubble Space Telescope.

Unfortunately we were unable to stream it live on YouTube, but you can now watch a video of the event here:

External link: https://www.youtube.com/watch?v=OitCXcthB-k

In the Q&A session, some technical questions came up which John needed to check with the specialists at NASA. Based on his conversations this afternoon, he would like to add the following:

The image is nicknamed the “Cosmic Reef” because it resembles an undersea world.

Although NGC 2014 and NGC 2020 appear to be separate in this visible-light image, they are actually part of one giant star formation complex in the Large Magellanic Cloud, about 163,000 light years distant.. The star-forming regions seen here are dominated by the glow of stars at least 10 times more massive than our Sun. These stars have short lives of from a few million to a few tens of millions of years, compared with the 10,000 million-year lifetime of our Sun.

The blue-coloured nebula (NGC 2020) below NGC 2014 has been shaped by one mammoth star that is roughly 200,000 times more luminous than our Sun. It is an example of a rare class of stars called Wolf-Rayet stars, which have unusual spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. Their surface temperatures typically range from 50,000 K to around 200,000 K, hotter than almost all other stars. They are thought to be the descendants of the most massive stars. Wolf-Rayet stars are very luminous and have a high rate of mass loss through powerful stellar winds. The star in the Hubble image is thought to be 15 times more massive than the Sun, although it may have been more massive in the past prior to shedding a considerable amount of its mass.

The Wolf-Rayet star at the centre of NGC 2020 is unleashing powerful winds, which have cleared out the area around it. It has ejected its outer layers of gas, sweeping them around into a cone-like shape, and exposing its searing hot core. The star appears offset from the centre because the telescope is viewing the cone from a slightly tilted angle. In a few million years, the star is likely to explode as a supernova. The brilliant blue colour of the nebula comes from oxygen gas that is heated to roughly 11,000 degrees Celsius, which is much hotter than the hydrogen gas surrounding it.

Information courtesy of NASA, ESA and STScI

[Dominic Ford]

The times are as follows (all times in BST):

Friday 24 April – 12 noon – A Special Image for the 30th Anniversary of the launch of the Hubble Space Telescope
Saturday 25 April – 2.30pm – Spring webinar

I’m not sure where you saw these erroneous times.

[Nick James]

Great image from Hubble. I have an image from Chelmsford taken 14 hours earlier and it is interesting to compare the two. You can see why having a 2.4m telescope in space is such a good idea. In three days time it will have been in orbit for 30 years. Let’s hope they keep it working for a long time to come.

[Andy Wilson]

Thanks for pointing this out Jack.

On a similar topic, the BAA is fortunate to have been given permission to broadcast a webinar for A Special Image for the 30th Anniversary of the launch of the Hubble Space Telescope this Friday 24th April at midday. More details here:

https://britastro.org/node/21425

Andy

[Paul G. Abel]

Hi all,

I hope everyone is keeping safe and well.?  Just to let you all know that issue 3 of Messenger- the Mercury and Venus Section newsletter is now available for download on the Section website.  Venus will continue to dominate our evening skies until it reaches inferior conjunction on 3rd June.  Now is an excellent time to observe our neighbouring world- especially if you have a small telescope as the apparent diameter is now quite large and the crescent phase (I think) is one of the loveliest aspects of Venus.  If you need any help or assistance in observing Venus please get in touch!

Best wishes,

-Paul

[David Basey]

In the March 1972 issue of Sky and Telescope, A.T. & L.G. Young discuss methods of near Sun observing revolving around keeping the Sun’s light off the primary optics. They cover in some detail the use of tube extensions and occulting disks to achieve this.

They cite the following examples:

• Using the dome to block the Sun, the 82″ reflector at McDonald observatory routinely observed at 12^o elongations and down to 7^o at reduced aperture. 
• Using a sun shield extending 14′ beyond the dome of the 24″ reflector at Table Mountain Observatory, California the authors were able to get down to 4.5^o at full aperture and 3^o with acceptable aperture loss. This did need an assistant to monitor the shade’s position and adjust as appropriate.

The authors make the point that a solid tube reflector has in effect a built in sun shield.

Certainly it is desirable to keep the Sun off the main mirror for all sorts of reasons. I have a couple of times felt it prudent to curtail observations due to smoke emanating from the end of the telescope tube where an off-axis image of the Sun was burning into the woodwork! Although disconcerting there was no danger to eyesight, being off axis there was no way that the Sun’s image could enter the eyepiece on a Newtonian reflector. This happens quite some distance from the Sun and is a timely reminder that this is close enough. Personally, with my setup, I would consider even 10^o too close.

Unless you really know what you are doing like Chris and have suitable equipment, again like Chris, don’t do it. You only have one set of eyes!

David.

[Alan P Buckman]

We did it as Microsoft Team because the leader was conversant with it. Skype will work just as well. There is a ‘Share desktop’ button and ‘invite more people’. What it needs is a person with the imaging / telescope equipment hooked up to a computer to offer to host and you need a group of participants to  link up with. A great deal of sharing of Skype addresses is necessary.

The Microsoft Team meeting – I received an invite being a member of Monkton Stargazers and was able to use video. It was quite manageable with a dozen and we could all take our turn discussing whilst the host was operating the equipment.

[Alan P Buckman]

Hi Grant. The bearings that take a hit when the telescope is accidentally knocked are the 22mm dia ones both ends of each slow motion axle. The mount was designed with roller bearings in these positions and they do not cope well with large sideways forces. On the mounts we (AWR) have serviced ther ehave been distinct dinks on the rotation of some of the bearings we have removed. These must run smoothly else you will get unexplained jumps in the tracking especially visible in CCD work. I would not bother changing the large bearings on the primary axles. Certainly I would clean out the old grease. It is a magnet for contamination.

[Alan P Buckman]

Hi all. We had a local virtual astronomy observing session with a remotely operated telescope at Monkton Nature reserve (Thanet in Kent) hosted using Microsoft Team meeting. there were a dozen of the Monkton Stargazer group present. Wonderful experience with the chit chat and pointing the telescope to an object, taking an image and post processing whilst we all watched. I would recommend any group if they can share a screen which is controlling a telescope to work this way and invite others to view.

[Tom Moran]

Hi Grant.

I converted my NEQ6 pro with the Rowan kit. I was able to watch my good friend and telescope builder Len Clucas convert his. I am a total novice regards this sort of thing but even I was able to do it; slowly! It took me roughly a couple of days. The mount is quieter and smoother with improved pointing accuracy. My guiding graph on PHD is much flatter. It’s been installed for a couple of years now with no issues. Good luck. Tom Moran.

[Nick White]

Hi Jeremy, not different plans as such but enjoying taking a closer look at the brighter objects. For example, attempting to split the trapezium in binoculars, observing Venus more closely than usual through the 10″ reflector, that kind of thing. I even managed to see the ISS a few times through the telescope the other night. Simple enjoyments.