Verclause, spring 2024

10 April - blog 2 of 2

Astronomers complain about the weather. That's just what we do. Clouds are our archnemesis but we like to gripe about transparency, seeing and just about every other atmospheric effect, too.

This astrotrip the weather left little to be desired during daytime, but nights were a different story. Clouds aplenty and often not even a promise of clear skies. That was unfortunate, but as it goes for every cloud, there was a silver lining: literally thousands of files for CSOG 3.0 required editing. Nothing fancy, just work required to tidy up a publication that is expected to approach (if not exceed) 50,000 pdf's. For that purpose I dragged along a screen to convert the kitchen of the gîte into a temporary office space. The result is that I managed to complete all work that I intended to complete and more... and I now wish I had a fireplace in my home office, too.

The surroundings of the gîte are typical for this region of France. Forests, rocky rural roads and no shortage of stunning views. This time of year the deciduous trees were becoming green and even the cat at the local supermarket shifted color.

The wait for clear skies lasted until the final night. That evening on 10 April the clouds promised to stay away until well after midnight. With a bit of luck, I would have been able to squeeze in about 4 hours of observing before getting at least a few hours of decent sleep with the homebound drive ahead of me. The end of evening astronomical twilight that night was when the clock stroke ten and 20 minutes prior to that I was all set to kickoff the session with some double stars in Hydra. The Moon was still up but only a very thin crescent and about to tuck away behind the hills to the west.

Did I mention astronomers always encounter something that's detrimental to their endeavors? I may have left one out: desert sand, in the atmosphere. I knew it was there as rain deposited plenty of it on my telescope's tripod plate, but not having had the opportunity to gaze at any stars during the week past, I had not yet encountered its optical effects.

First double 17 Hydra a.ka. STF1295 was nice. WDS lists spectrum A for both components but I found them clearly contrasting with A bright yellow and B white.

STF1302 is almost 10 degrees farther north, but centering the double in my eyepiece I could tell something was off. The view altered from a moment when components A and B were clearly discernible as individual stars, to a single, wooly elongated smudge and back. Other stars in the field displayed the same effect. Weird. I had little doubt that sand in that part of the atmosphere, closer to the southern horizon, was to blame. It definitely wasn't the seeing as it was not a tremble but intermittent, irregular fuzziness instead. Just another phenomenon stargazers have to deal with. I recalled a night in April 2015 when there was such an abundance of Sahara sand in the sky I decided to not uncover the scope altogether.

17 Hydrae (STF1295)
16mm Nagler T5: AB split. A nice double.
A is bright yellow, B is white, clearly contrasting.

9mm Nagler T6: Using this magnification A is yellowish. The spectra in WDS2023.12 for A and B are A2 and A7 respectively, but with use of 16mm, too, A is clearly yellow, not a deep hue but clearly contrasting.

STF1302
16mm Nagler T5: AB just split, C is visible with AV, ABC split.
A and B are both yellowish.
The stars are remarkably "wooly" at times, suspected to be due to desert sand in the atmosphere; it's clearly not due to the seeing. At these moments AB is elongated on the PA but not split and no individual stars can be discerned.

9mm Nagler T6: AB split. The view 'jumps' notably from good to bad and back. All stars in the field become 'wooly', it's not 'trembles' from the seeing.

With only these two observations I left Hydra alone and shifted my attention to the great bear in the zenith instead. Of the 37 galaxies in CSOG's 12-14" Gx-12 guide, 17 were on my wanted list for first time observations. The remaining 20 were faint fuzzies I observed only under Dutch skies and back in the year 2011.

Both NGC3191 and MCG+08-19-017 (PGC30128) are small galaxies that lack detail, but seeing them together made for an above-average view. The images below - as all CSOG images in this blog - are from upcoming new or updated CSOG 3.0 editions.

Both galaxies are visible.
The eastern galaxy NGC3191 is larger and brighter than the western galaxy MCG+08-19-017 (PGC30128) is, without AV almost round, with AV a faint, slightly north-south elongated glow, gradually brighter in the middle, no nucleus visible.
The western galaxy MCG+08-19-017 is a small, faint, round glow, no detail visible. Closer to NGC3191 than MCG+08-19-017 is, is a mag. 14.5-15 star.

The galaxy that followed, NGC3198, did reveal quite a lot of detail. No arms could be discerned but irregularity was notable.

Quite a large, quite bright, NE-SW elongated glow. With AV irregular and clearly brighter in the SW-2/3 part. With AV a small, even brighter part of the galaxy is visible centrally in the galaxy, slightly elongated NE to SW containing the small, stellar nucleus of the galaxy. With AV the galaxy is most irregular to the SW of nucleus. The irregularity is notable but no arms are discernible.
The galaxy gradually faints towards the SW and more abruptly towards the NE.

The first of 3 KPG pairs observed in this session (actually 4, but the pair that forms NGC3406 is part of Holmberg 217) was KPG 242. This wide pair of elongated streaks is separated by a mag. 10.5 star.

Both galaxies are visible.
The WNW galaxy A - MCG+08-20-004 (PGC31697) is clearly brighter than the ESE galaxy B - MCG+08-20-011 (PGC31720) is, a NE-SW elongated little streak, gradually brighter in the middle, no core and no nucleus visible.
The ESE galaxy B - MCG+08-20-011 (PGC31720) is elongated in the same direction as A - MCG+08-20-004 (PGC31697) is but is clearly fainter, even in brightness without AV, with AV gradually slightly brighter in the middle. To the east is a mag. 14 star.
In between the galaxies and slightly towards the north is a mag. 10.5 star.

Just over half a field of view to the south of the KPG is NGC3320. Another nice one, relatively bright and sporting a star on its southwestern edge.

Quite a bright, NNE-SSW elongated glow with a mag. 13 star (4UCAC687-052792) on the SW edge. The galaxy is clearly brighter SSW of the middle, the SSW-2/3 of the galaxy is the brightest. With AV the transition to the brighter SSW part is slightly more sudden and the brighter part is irregular. No core and no nucleus visible.

Next up was MCG+08-20-033 (PGC32536) and that smudge contained a surprise. It's a small one but its core is very bright and the transition from the outer regions to that brighter core is very sudden.

Without AV a slightly east-west elongated glow, gradually brighter in the middle with a bright nucleus that is clearly visible without AV. With AV the galaxy is more elongated and suddenly brighter in a bright, notable core that is elongated in the same direction. The sudden transition to the core is notable. The nucleus is just a bit west of the middle.
The galaxy is in the right angle of right angled triangle with a mag. 11 star to the south in the shorter leg of the triangle and another mag. 11 star 2 1/2 times that distance towards the west in the longer leg of the triangle.

I figured it would make for a nice Object of the Week on Deep Sky Forum, hence the images for the OotW guide for week 17 above.

Aforementioned Holmberg 217 revealed its galaxies. Two galaxies form NGC3406 and while I did not see them separately, I could determine there were indeed 2 of them. Much fainter NGC3410 to the east-southeast was visible too, but very faintly and only with use of averted vision. Nearby PGC2386525 did not reveal itself.

The galaxies that form Holmberg 217 are visible.
The two galaxies PGC32580 (KPG 253A, SW) and PGC93106 (KPG 253B, NE) that form NGC3406 (Holmberg 217A) are visible, without AV an irregular glow, with AV even more irregular and brightest in the SSW part where the glow is wider east to west and in which a nucleus is visible. The NNE part of the glow is clearly fainter and is elongated NNE to SSW: with that it's clear that there are two galaxies.
To the ESE of the galaxies that form NGC3406, NGC3410 (Holmberg 217B) is visible, a faint, round glow, only visible with AV, no detail visible. To the ESE of NGC3410 is a mag. 15 star, farther to the SSE is a mag. 13 star.
PGC2386525 to the SE of NGC3410 is not visible.

Two more KPG's made it into my eyepiece this session: KPG 260...

Both galaxies are visible.
The NNE galaxy B - MCG+08-20-063 (PGC33138) is brighter than the SSW galaxy A - MCG+08-20-061 (PGC33126) is, a rond glow, quite suddenly brighter in a small, round core with quite a bright nucleus that is just visible without AV.
The SSW galaxy A - MCG+08-20-061 (PGC33126) is fainter than the NNE galaxy B - MCG+08-20-063 (PGC33138) is, without AV even in brightness and slightly elongated east to west, with AV slightly more elongated and gradually brighter in the middle, no nucleus visible.
To the SW is the fainter galaxy MCG+08-20-060 (PGC33107).

... and KPG 262, that also goes by Vorontsov-Vel'yaminov 1408.

Both galaxies are visible.
The SSW galaxy A - MCG+09-18-075 (PGC33342) is slightly brighter than the NNE galaxy B - MCG+09-18-074 (PGC33357) is, a round glow, without AV the nucleus is at the limit of visibility, with AV the galaxy is gradually brighter in the middle.
The NNE galaxy B - MCG+09-18-074 (PGC33357) is fainter than the SSW galaxy A - MCG+09-18-075 (PGC33342) is, slightly elongated NNE to SSW and even in brightness, no detail visible, no core and no nucleus visible.
A nice pair of galaxies to compare round (A) with elongated (B).
1/4 FoV to the SSW is the galaxy MCG+09-18-073 (PGC33325).

Observing NGC3595, I noticed the mag. 8.5 star to its north-northeast to play a little optical trick. It was at times creating spikes towards the north and south. Desert sand in this part of the atmosphere, too, or..?

A north-south elongated streak, gradually brighter in the middle, the nucleus is visible without AV. With AV the galaxy is more elongated and more of the fainter outer regions of the galaxies is visible.
To the NNE is a bright white mag. 8.5 star (SAO43659).

The galaxy that revealed the most detail of all the galaxies observed in this session and with that the highlight of the session, was NGC3583. Its core is offset and that core clearly showed irregular structure. Arms could not be discerned, but there was a hint. A very pleasing observation.

Quite a large, irregular glow, suddenly brighter in an ENE-WSW elongated core that is clearly irregular with AV and that is brightest WSW of the middle. In that brightest WSW part clearly irregular structure is discernible with AV. With AV the glow of outer parts of the galaxies in faintly visible on the SE side, on the north side, a faint, smaller part is visible using AV that curves towards the west, but that's not clearly discernible as an arm of the galaxy. A nice galaxy.
PGC2315061 to the NE is not visible.
To the SSE is a mag. 14 star, five times that distance to the SW is a mag. 12 star with the galaxy NGC3577 NW thereof.

MCG+09-19-060 (PGC34971) surprisingly did not make it into the NGC or IC list. It isn't too faint and its elongated shape is quite nice.

A faint, clearly NW-SE very elongated streak, even in brightness without AV, with AV gradually subtly brighter in the middle. No core and no nucleus visible. The elongated shape is notable.

It was then when the God's of the heavens touched the dimmer. The galaxy literally faded in front of my eyes. I leaned back from the eyepiece to see only the brighter stars of Ursa Major clearly visible, and little Alcor struggling to remain seen. The clouds were back, with vengeance and much earlier than expected.

It was the end of the session and with that the end of this astrotrip. The next morning I packed the car and set out for the return journey. 1000 clicks to drive, but nothing compared to the mouse clicks of the week past, editing CSOG content. Time well spent in splendid surroundings. V3.0 is well on its way.

Observations

28 galaxies
2 double stars
Total: 30 observations
First time observations: 16 objects

Details of the objects observed in this session are in the table below.

click here for my observing log

to top of table