We had a great meeting in Gothenburg with the variable star group SAAF/V, our third spring meeting in four years, so it is becoming something of a tradition. Here are some pictures:
Low sunspot stats
Paradoxically as it may sound, I find observing the sun these days very exciting. Few sunspots show up – today’s lunch-break observation with the 90mm Maksutov showed 3 groups and 6 spots – and the maximum last year of solar cycle 24 was very weak. It seems to be one of the weakest cycles since regular observations commenced in the mid-18th century, but by no means is it the weakest cycle sunspot-wise.
So even though there are not much action on the solar disc these days, being there to observe this feeble solar activity is very interesting and it feels meaningful to be one of stations of the network of observers reporting data to the international sunspots data centre. On any given day these at the moment, we are about 25 stations reporting observations, so it really feels that one is making a contribution to the centuries-long series of sunspot data.
Sometimes, in monitoring celestial phenomena, non-activity or low activity is also an interesting fact that would never be known had observers not been there to document it.
C/2014 Q2 Lovejoy: yet another comet
I observed C/2014 Q2 Lovejoy on January 14:
magnitude: 4.0
method: Sidgwick
comp stars: 5 Tau (V= 4.1) and omi Tau (V=3.6).
15×70 binoculars
DC=6
The comet was a very easy catch from my urban location, one of the brightest comets I’ve ever seen.
It was a fine sight. It also got me thinking about comets of the past, and I decided to spend some time with old observing journals and other sources to try to put together a personal cometography.
I remember my first comet. I’m pretty sure it must have been comet Austin (C/1982 M1) also known as 1982G. I was 15 years old, very much interested in astronomy, and this was my first comet which made the observation memorable. Passing through Ursa Major close to Canes Venatici, it was easily seen using either the 8×40 binoculars or the homebuilt monocular concocted from a 135 mm f/2.8 photographic tele lens plus Kellner and Ramsden eyepieces I also used. I observed from under the dark skies of Anderstorp, where I was born and lived until the age of 19.
Next memorable object was comet Halley; I saw it both on the inbound leg in 1985 and in the spring of 1986. I also remember a night at the Lund Observatory station Jävan, where I manned one of the telescopes, a C14, on a Halley-themed open night at the observatory. We had long queues lining up in the cold outside the dome.
Next comes Bradfield C/1987 P1, also known as 1987s, which I observed first at 25 October 1987. By then I was a 20 year old student at the Lund University, still an amateur astronomer. It was close to the horizon, but in my 4 inch f/4 Newton I determined its magnitude to be roughly 5.8. I observed it further on on 3 November, 8 November, 18 November (tail visible).
Next came comet Liller, 1988a, observed on 11 April 1988 using my trusty old 2.4 inch refractor and my homebuilt 4 inch f/4 Newton. My old observing log book tells the tale of an almost stellar central condensation, and a straight tail about 25′. With 8×40 I estimated the magnitude to be about 6.0. I observed together with Botvid Heijel, one of my long-time friends in the local astronomy club, during a visit to my parents’ place. Just a few nights later, on the night of 14-15 April, I observed together with Anders Johannesson at the Jävan station. Liller was in Andromeda and estimated to be 6.5 using the finder of the Lund Observatory C14 (a magnificent night during which we, among other things, observed southern objects such as M83).
According to my journals, the next comet observed was 109P/Swift-Tuttle. On the evening of 30 October 1992, it was estimated to be about 7 magnitude.
This observation was made at about the same time as I drifted out of amateur astronomy. Other interests filled my days (and nights!), and this old hobby now became more and more of a memory, and my telescopes, cameras, equatorial mountings, binoculars et cetera gathered dust. I could not, of course, fail to observer C/1996 B2 Hyakutake and C/1995 O1 Hale-Bopp. Of these two, Hyakutake was the most memorable. I doubt I will ever see such a comet in my life time again, with a tail that stretched some 30-40 degrees over the firmament.
Another memorable comet during these years when I was not an amateur astronomer was discovered by myself in October 2007 (and quite a few other observers, including the British amateur Edwin Holmes back in November of 1892). I had been out shopping, and as I parked my bicycle I habitually looked up in the sky and found a bright star where none should be, in Perseus. My initial thought was that it was a nova (Perseus being in the Milky Way). I went inside, turned on the computer and soon found the Sky&Telescope story of the flare-up of comet 17P/Holmes.
Some years later, I became an amateur astronomer again. In fact, my re-entry into the world of amateur astronomy can be dated quite precisely to the evening of 25 October, 2011. It took some four months before a bright comet turned up: on March 3 2012, I observed C/2009 P1 (Garradd) at mag 7.4 using 15×70 binoculars. It was high in the sky; on March 4 it was observed at 7.3.
Next comet was 168/P Hergenrother on 6 October 2012, estimated at 9.8 (Sidgwick method) in my 20 cm Newton at 120x. It was a condensed object with an estimated coma diameter of 0.5′.On 10 October 2012 it was observed a strongly condensed object at magnitude 10.0 and a coma diameter of 1′; there was a hint of tail or at least asymmetrical coma.
Next is C/2011 L4 PanStarrs, seen as an easy object in 15×70 binoculars on April 4 2013 close to M31. I had also seen it when it was brighter and closer to the horizon. It faded rapidly, on the evening of 15-16 May I observed it at 10.0 using my 20 cm Newton at 179x. It was then in the field of RY Cep, so finding suitable comparison stars was easy.
C/2013 R1 Lovejoy was observed on 27 November 2013 estimated at 5.6 in 15x70B. A fairly condensed coma.
C/2014 E2 Jacques was a fairly easy object at magnitude 7.0 on 23 August 2014 in 15x70B, coma diameter estimated at 6′. It was also observed on 25 August (mag 7.1, DC 5, no tail) and 27 August (mag 7.1).
All in all, I have observed 14 comets visually. Not many, compared to some of my fellow amateurs. I find comet observing to be fun once in a while and I try to observe the brighter objects at least if they are well placed high up in the sky (my regular observing location is surrounded by five story buildings).
V0446 Vul
The variability of this star was discovered by Lennart Dahlmark in a photographic patrol programme, using plates exposed from 1967 and onwards. It was announced in a publication in 2001.1 Two years later it got the official designation V446 Vul.
Dahlmark gave the type Lb, a slowly varying irregular variable. However, a handful of recent observations by me shows the variation to be rather fast:
Recent observations of V446 Vul
V0446 Vul is included in the ASAS survey, which also shows a rather quick semiregular variation on a timescale of about 100 days:
ASAS observations of V0446 Vul
I have used the Fourier period analysis tool (DC DFT) in Vstar to analyze the ASAS observations, and the result is 103 days.
V0446 Vul seems to be some kind of SR variable, rather than an Lb.
Update 26 August: now the VSX entry for V0446 Vul has been revised to show the new data.
- Dahlmark, Lennart. ”New Variable Stars Along the Northern Milky Way”. Information Bulletin on Variable Stars 5181 (2001). [↩]
C/2014 E2 (Jacques)
I observed C/2014 E2 (Jacques) with 15×70 binoculars tonight. Magnitude was estimated to be 7.0, using the Sidgwick method and an AAVSO sequence of comparison stars for the nearby V0465 Cas, coma diameter 6′. The observation has been reported to COBS.
The comet was very easy to spot and showed no tail. Observations with my 90 mm Maksutov Cassegrain at 50x and 187x showed no tail, and the comet appeared brighter and larger with the binoculars than with the telescope.
BRT queue
Four days later, and still no images from BRT. No big deal, but the queue seems to be rather long.
Update 25 August: a week after registration, the first four images came through. Quite good tempo, I think.
Update nr 2 26 August: yet four more images came through the queue.
Update nr 3 28 August: two more images. Summing up, ten images came through during eleven days. If this is typical of the average throughput of the BRT system, 3 pounds per month seems like a very good price, compared to Sierra Stars and iTelescope.
Update nr 4 17 September: one month, 20 completed images. Cheaper and deeper than iTelescope.
Update nr 5 17 October: yet another month, in which 27 images were taken. The tempo is quite OK.
Update nr 6 17 November: 19 images this month. After three months, the average cost per image lies at 14 pence = 22 US cents = 1.6 SEK. For comparison, the minimum price over at Sierra Stars (30 seconds on the Rigel 37 cm Cassegrain) is 42 US cents, while a 30 second exposure on iTel 5 (25 cm Newton) is 58 cents (lower when there’s a moonlight reduction in price).
So, not surprisingly BRT turns out to be cheapest of the three compared systems. That doesn’t mean that I will leave Sierra Stars and iTel for BRT. The latter system is cheaper, but I have greater control over what images will be taken, and when, using Sierra Stars and BRT.
I have kind of taken to BRT, though. The images are great, even though there’s often some trailing but I can live with that for my photometry of variable stars, they reach deep. The user interface is quite good, just like Sierra Stars it is of the fire-and-forget variety, iTel takes a bit more handling to get going, what with booking the scope and everything. And the BRT tempo suits me; roughly 20 images a month leads to images showing up every once in a while, perfect for some photometry during lunch breaks.
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Tagged BRT, iTel, iTelescope, remote telescopes, Sierra Stars
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Bradford Robotic Telescope
I like the BRT, when there’s no trailing the images are deep and I can measure down to the 16th magnitude or so. The major drawback is, I would say, that the telescope is severely oversubscribed. I’ve been off BRT for quite some time, instead using iTelescopes 4 and 5, but now I’ve resubscribed. My old account was of a type that don’t exist anymore, and instead I opted for the 3 pounds per month type of account, which lets you have ten images in the queue.
Three pounds per month leads to a quite cheap price per image compared to iTelescope and SierraStars, provided those images gets taken. Wonder how long it takes before those ten images gets through …
LD 323
LD 323 is one of the Lennart Dahlmark variables that so far has not made it into the GCVS namelists; and lacking an official name we will have to keep calling it LD 323 for some time. I have observed it on and off for about a year. There is also a series of observations by Steve Girard in late 2013.
The star varies quite regularly:
A year's observations of LD 323.
I have used VSTAR to analyse Girard’s and my observations. The Fourier transform method (DC DFT) in VSTAR gives a period of 88.9 days (using only the V data), which is for all practical purposes identical to the result, 88 days, that Sebastian Otero got in his analysis of NSVS data for this star.
Nova Cygni 2014
Nova Cygni 2014 has been behaving in an interesting way; overlayed on the general rise to max and decrease after max, are variations with an amplitude big enough to be prominent in visual observations.
Observations of Nova Cyg 2014 from the AAVSO archive
I have observed the nova a number of times, using the 90 mm Maksutov-Cassegrain. It is easy to find, with star hopping-friendly asterisms nearby. It is the third nova I’ve observed recently, the other two being Nova Cep 2014 and Nova Del 2013, also known as V0339 Del.
Guerilla astronomy
The weather forecast for the coming days shows some chances of partly clear skies at night, but the odds are not very good.
As usual.
My 20 cm Newton is kind of bulky, and not the type of instrument one quickly sets up to observe through gaps in the clouds (I don’t have it permanently mounted, have to carry it outside for observing). No, for nights such as tonight, I rather prefer my 15×70 binoculars and my 90mm Maksutov-Cassegrain, small instruments that are easily and quickly set up in my backyard.
90mm f/13.9 Maksutov with 8x50 finder. The telescope has a quite decent limiting magnitude of 12.4 with my 6.7 mm Explore Scientific eyepiece, even when observing from my urban location.
In a number of minutes, one is set up to observe. The pair of 15×70 binoculars is a fast instrument, and the 90mm Maksutov-Cassegrain reaches 12, even 12.4 on a good night (from my urban location). I use the same 8×50 finder with the Mak and with the 20 cm Newton, which speeds up starhopping. It is mounted on a Triton alt-az mount which is sufficiently stable, even at 185x.
