Its hard to believe that a year has gone by since our Solar System neighbour Venus seemed to be around for ages and riding high in our evening sky during the late winter and spring months. This year, after its superior conjunction on March 25th 2021, Venus will once again start to become part of our evening sky (which makes observation of the planet more "convenient" for many than when it is an early morning object) until towards the end of the year. Unlike last year's evening appearance, for many locations this coming "visit" the planet will not be as high in the sky and having a low and or flat western horizon would be beneficial. However Venus, which is similar in size to our Earth but has a temperature of ~450 degrees and a crushing atmospheric pressure ~90 times that of our own planet, is always worth pursuing visually or photographically if you can.
As April progresses, Venus becomes more visible in the evening sky and where it appears in your sky will depend on your location. One upcoming event to keep an eye occurs on 25th April. After sunset low in the north west horizon -1.5 magnitude innermost planet Mercury will be ~1.2 degrees away from its Solar System neighbour Venus which will be shining at -3.8. This encounter will be a nice sight in binoculars and low power short focal length telescopes. This also an ideal photo opportunity too a good opportunity to see Mercury if you have not seen it before.
On the evening of 13th May Venus will make a nice pairing with a thin crescent Moon which will be to the upper left of Venus. Mercury will be close by (~2.5 degrees) being to the upper right of the Moon. This will make a nice photogenic triangle.
There will also be crescent Moon-Venus encounters on the evenings of 11th and 12th June when the Moon will be below right and then above left of Venus respectively by ~6 degrees.
On the evening of July 12th shortly after sunset our other Solar system neighbour Mars will be close-by (~1 degree) and below left of Venus with the slim crescent Moon nearby.
You will need to set the lens at infinity and experiment with exposure times for the sky brightness, lens aperture and camera ISO being used. A tripod to support your camera gear while photographing these events is highly recommended. The Astro & Nature Photo Tripod w. Fluid Head and quick mounting plate (#2451020 , € 235,-) is an ideal sturdy tripod to carry your camera (or spotting scope) gear up to a total of 3kg. It features quick easy removable mounting plate, a fluid head with locking handles for smooth altitude and azimuth movements and extending legs with rising central column for tripod height adjustment up to a maximum of 1.89m.
This time around Venus apparent size will go from just under ~10" near the end of April where it will be ~99% illuminated, to just over 12" near end of July with ~82% illumination. During August its apparent size will increase slightly to ~14.5" and 75% illuminated, but by this time the gibbous phased Venus will be heading towards the horizon making viewing a little more difficult.Venus will exhibit a crescent phase as the year draws to a close and it will appear larger in a telescope than earlier in the year but will be lower in the sky. The image to the left shows Venus very early in December when it will be only ~28% illuminated but being ~40" in size (~4x larger in apparent size than it was in April). However Venus will be very low down in the SW sky and as mentioned before a low and flat horizon would be ideal at this time depending on your location.
Orthoscopic eyepieces are a favourite with planetary observers and our Classic Ortho 6mm, 1¼" Eyepiece (HT-MC) , Classic Ortho 10mm, 1¼" Eyepiece (HT-MC) , Classic Ortho 18mm, 1¼" Eyepiece (HT-MC) are ideal for viewing Venus (as well as other planets too). These parfocal eyepieces, which are the same optical design as the old Zeiss Jena Orthoscopic models, have a 52° apparent field of view and have high-transmission multi-coatings on all the glass-to-air surfaces to give very sharp and high contrast views. The apparent size of Venus will not be large during the months of April to August so if you want to get more magnification the Baader Q-Barlow 1.3x/ 2.25x (#2956185 , € 55,-) will give a useful (but rare) 2.25x image amplification.
If you are using multiple eyepieces at the telescope, the Q-Turret 4x Eyepiece revolver (#2957010 , € 55,-) which is available as an accessory on its own or Baader Q-Turret Eyepiece Set (eyepiece revolver, 3x Classic Ortho, 1x Classic Plössl, 1x Q-Barlow 2.25x) (#2957000 , € 280,-) , makes simple work of swapping between different eyepieces (and magnifications) simply by rotating the turret to bring another eyepiece into the light path.
Venus is very bright in our sky and to cut down its glare you can use our Double Polarizing filter to vary the brightness of the planet through the eyepiece which may allow you see some cloud detail. This filter can also be used with a planetary imaging camera too. The filter is simply screwed into the barrel of an eyepiece, Q-turret nosepiece mentioned above or a nosepiece of an imaging camera. It is also possible to screw the filter into the nosepiece of a diagonal so it is not necessary to remove the filter when swapping between eyepieces. Our colored planetary filters can also help with observations with red, yellow and blue versions being useful to increase contrast. If you want to swap between different filters our Universal Filter Changer makes this job easy and we provide many different telescope-side and eyepiece-side adapters to suit.
For those who want to image the planet, there are a number of accessories you can help. Centering Venus (or other planet or Lunar feature) on a small sized sensor can be difficult and frustrating and this is where our Baader FlipMirror II Star Diagonal (#2458055 , € 228,-) (BFM II) can be of benefit. There many different telescope side, eyepiece port and camera port adapters for this that are available to suit your equipment. In use, centre Venus in your eyepiece, flip the BFM II diagonal mirror up and the planet should be visible in your camera's field of view.
The BFM II is also available as part of a complete photo bundle which includes 2" telescope side nosepiece, two 1.25" eyepiece holders, 10mm orthoscopic eyepiece for viewing and centering and a QHY-5-III-462C colour high speed low noise planetary imaging camera. This is an ideal package with everything you need to get into Solar system planetary imaging.
The Q-turret mentioned previously is not just limited to eyepiece use only. You can use a planetary imaging camera alongside your eyepieces so you can easily swap between your visual and imaging configurations. The Q-Turret eyepiece and barlow set is also available combined with the QHY-5-III-462C planetary camera for those who want such a visual and imaging combination package.
With Venus being smaller in apparent size you may want an increase in image amplification and the versatile Baader Q-Barlow 1.3x/ 2.25x (#2956185 , € 55,-) can be used for imaging. Also our Classic Ortho eyepieces are ideal for doing eyepiece projection imaging with the OPFA Eyepiece Projection Adapters too.
The Baader U Venus Filter, with a bandwidth of 60nm from 320nm-380nm with an 80% peak transmission, will allow you to record the Venus in the UV spectral region to capture cloud structures in the Venusian atmosphere with telescopes 5-6" aperture and above (ideally recommended).
We wish you good luck and clear skies in chasing Venus over the coming months and we look forward to seeing the results of your visual and imaging work.
About the author: Lee Sproats
Dr. Lee Sproats has been interested in astronomy since watching Star Wars in 1977 and has appeared on the UK Sky at Night TV programme. He then went on to study Astronomy where he obtained a degree and then a PhD in the subject at University College London/Mullard Space Science Laboratory. He has worked in Australia in radio astronomy and used optical/infrared telescopes on Hawaii and La Palma and Lowell and Kitt Peak observatories in the USA. After working for the University of Surrey to promote the use of computers for teaching in UK higher education and then as an IT trainer for a stock market company, he went on to work for Greenwich Observatory Ltd where he ran their northern branch and then worked for David Hinds Ltd dealing with our and Celestron products. He is often involved in flight excursions that take passengers to observe the northern lights, has led trips to see the great USA 2017 eclipse near Hopkinsville and was lead astronomer onboard a specially chartered 737 to view the 2015 total solar eclipse at 38,000ft. Lee`s astronomical interests include Lunar observing, astrophotography, photometry and pro-am collaborations.
Since David Hinds stopped operation in December 2020, Dr. Sproats works for Baader Planetarium as our UK representative/consultant and is responsible for looking after our UK/Eire dealers, dealing with Baader Planetarium/PlaneWave/10Micron product support, writing articles and also is involved in our large telescope and observatory instrumentation projects.